Interview with Mark Jensen

Dublin Core


Interview with Mark Jensen


Hanford Site (Wash.)
Richland (Wash.)
Kennewick (Wash.)
Nuclear reactors
Nuclear reactor accidents
Chernobyl Nuclear Accident, Chornobylʹ, Ukraine, 1986
Nuclear energy
Nuclear power plants
Nuclear fuel rods


Mark Jensen moved to Richland, Washington in 1961 as a child and grew up in Kennewick, Washington. Mark began working on the Hanford Site in 1981.

An interview conducted as part of the Hanford Oral History Project. The Hanford Oral History Project was sponsored by the Mission Support Alliance and the United States Department of Energy.


Hanford Oral History Project at Washington State University Tri-Cities




Those interested in reproducing part or all of this oral history should contact the Hanford History Project at, who can provide specific rights information for this item.



Date Modified

2017-04-12: Metadata v1 created – [A.H.]


The Hanford Oral History Project operates under a sub-contract from Mission Support Alliance (MSA), who are the primary contractors for the US Department of Energy's curatorial services relating to the Hanford site. This oral history project became a part of the Hanford History Project in 2015, and continues to add to this US Department of Energy collection.

Oral History Item Type Metadata


Douglas O’Reagan


Mark Jensen


Washington State University Tri-Cities


Douglas O’Reagan: Okay. To start us off, would you please pronounce and spell your name for us?

Mark Jensen: My name is Mark Jensen, M-A-R-K, J-E-N-S-E-N.

O’Reagan: Great. Okay. My name is Douglas O’Reagan. I’m conducting an oral history interview with Mr. Jensen on March 25th, 2016. The interview is being conducted on the campus of Washington State University Tri-Cities. I’ll be speaking with Mr. Jensen about his experiences working at the Hanford site and living in the Tri-Cities. To start us off, can you tell us a little bit about your life before you came to Hanford?

Jensen: Well, my mother moved to Richland to teach English at what was then Columbia High School, now Richland High School. She was a single mother with five children. So I started school at Jefferson Elementary in Richland in kindergarten. When I was in third grade, my mother remarried, and I was adopted by my new father. He was a long-time Hanford worker. Anyway, so I grew up in the Tri-Cities. We moved to Kennewick when I went into fourth grade, and I went through the Kennewick School District after that, and graduated from Kamiakin High School in 1974. Went to Washington State University, got a degree in forestry, thinking that would get me out of the Tri-Cities, because there aren’t any forests here. Unfortunately, there weren’t any jobs in forestry. So I came back home to live with my parents, and my dad mentioned that N Reactor was hiring reactor operators. So I applied, and got a job as a reactor operator.

O’Reagan: What time frame would it have been that your mother moved here?

Jensen: I was five, so that would have been 1961.

O’Reagan: Okay, great. Can you tell us about the schooling, the education, the schools in the Tri-Cities as you experienced them?

Jensen: Well, I went to Jefferson Elementary, like kindergarten through third grade. It was in an old building left over from World War II. It was probably a grade school built as part of the Manhattan Project. That’s all long since been torn down. Then when we moved to Kennewick, I went to Hawthorne Elementary school there. Building’s still there as far as I know. And then to Vista Elementary, then to Highlands Middle School—Highlands Junior High in those days. Then the Kamiakin High School which was brand new.

O’Reagan: What was life like as a kid in Kennewick?

Jensen: It was pretty routine, I guess. Went outside and played in those days instead of staying inside for video games. It didn’t matter how hot it was outside, we’d go out and play baseball all day usually, and things like that. Then just going to school during the school year and doing whatever during the summer. When I was growing up, before my mother remarried, she would work in the summer and I was usually babysat by some of her students. After she remarried, then she stopped working during the summer. But I’m fairly certain that one of the reactor operators I worked with at N Reactor was one of my babysitters when I was second or third grade. But anyway.

O’Reagan: When you were sort of a teenager, what sort of stuff did you and your friends do for fun around the area?

Jensen: Usually, after doing our homework, we’d go outside and play basketball, every day, every night. We had a lighted basketball court. We’d play basketball all day Saturday and Sunday. When the weather was nicer, we’d play baseball or variants of baseball, since there were seldom enough people to make up a couple of teams. We used to go to baseball games—minor league baseball games—in the summer. A variety of different team names. There was a stadium in Kennewick called Sanders Jacobs Field that’s long since been demolished. That’s pretty much what we did, just mess around. Go bowling, things like that.

O’Reagan: Do you know what your step-father did at the Hanford site?

Jensen: He was a chemical engineer, and he worked at N Reactor and the older reactors designing systems for decontaminating the reactors. When I was in high school, he worked at the Tank Farms in the 200 Area. He was in charge of Tank Farm surveillance, and that was when the tanks started leaking—the older tanks first started leaking. So we got frequent telephone calls in the middle of the night that there was a leaking tank. Sometimes I’d hear my dad say something on the telephone, and the next day I would see that in the newspaper, as a Hanford spokesman said, kind of thing. That was kind of interesting.

O’Reagan: So I guess you were aware of the future environmental issues pretty early on?

Jensen: Yes. Yeah.

O’Reagan: Did that impact your life at all? Or was it sort of in the background?

Jensen: It’s just the way things were.

O’Reagan: So when you came back and were looking for a job and you first heard about this job at N Reactor, did you—was that something you were sort of excited about? Was it something you were--?

Jensen: It sounded interesting. I knew nothing about it. Not too many people knew reactor operators, although there were certainly plenty of them around here over the years. So I had no idea, really, what that job entailed. But it was a job, and it paid pretty good. So when it was offered to me, I accepted it.

O’Reagan: What kind of skill sets did it end up requiring you to gain?

Jensen: I had to learn a lot about how to operate complex systems, do valving in a precise, controlled manner so it was done correctly. Not so much working with pumps, other than checking to make sure they were running properly. I didn’t have to do maintenance kind of things. Then once I got my certification in the control room, I had to learn how to operate all of the systems, use the controls in the control room to do that, set everything up properly, and what to do in case of an emergency, or a reactor scram, or upset. Try and keep the reactor from scramming, things like that.

O’Reagan: What kind of training was involved?

Jensen: We started out, once we got into the certification program, we went into what we called phase one training. That basically started off with fundamentals training. We got some math and chemistry. Didn’t hurt that I had chemistry in college. It’s kind of funny—the week or two weeks we had in chemistry, I think I learned more than the two semesters of chemistry in college, because the instructor was so much better for the fundamentals class than the professor I had at college. But it might have also been because I was older and a little more mature.

O’Reagan: Was that onsite at Hanford?

Jensen: It was onsite at Hanford, out at N Reactor. We had some chemistry, math, a little bit of electronics, things like that. Started learning some of the various systems at the plant. Then we went back on shift for several months. I can’t remember now how long, I mean this is almost 40 years ago, so it’s kind of hard to remember everything. So when we went back on shift, we were given a packet of stuff that we had to study on our own and learn while we were assigned to do other jobs throughout the plant. Then we went back into class, into phase two, and studied more systems, and started learning how things in the control room worked. I can’t remember if there were four phases or three phases, but each time after a phase ended, we had an exit exam. Then we went back to shift, with more stuff to do in between the regular job stuff. At the end of all of the phases, we took an eight-hour written exam. Theoretically, if you failed the written exam, they could fire you. Or they could just reassign you as a non-certified operator. Some people did that after they failed. They just said they didn’t want to continue. But generally they gave you a second chance. Well, I passed the first time, so didn’t have to worry about that.

O’Reagan: How long did that process take?

Jensen: Started probably in February or March of ’81. I was completely certified in June of ’82. So it was probably about a year and a half for the total process. But they were in a hurry to get people certified, because there were a lot of older operators who were getting ready to retire. So they needed to get people in there and get some experience before they lost too many of the older, experienced operators. So after the eight-hour written exam, we had to study for what we called the demonstration exam. That was in the control room, and an instructor would say, okay, Mark, how do you set this console up for operation? You are going to do this job, show me without actually doing it--because it was in the real reactor—how you would do it. Later on, we had a simulator that was pretty much an exact duplicate of the reactor, and then you could actually do the things in the simulator. But for my demonstration exam, it was just point out what you would do. When we passed that exam, we actually got a pay raise. We went from what we called a Grade 18 to a Grade 21, and got a nice little bump in pay. Then you studied for your oral exam. That one, you went before an oral board. There was a representative from operations, a representative from training, and a representative from nuclear safety. They all had a certain set of questions to ask, and any one of them could come in at any time with follow-up questions. So that—I think that took me six hours. And I passed that, so then I was a certified operator. Except that operations would not sign your certificate until you demonstrated that you could handle the jobs. So when I went back on shift, I was assigned to an experienced operator. So we rotated through various positions in the control room, and I followed him around. Initially, he would do things and tell me what he was doing. Then he would have me do it, but he would tell me what to do. And then when he was pretty satisfied I knew what I was doing, he would just sit back and let me figure out what I was doing. And then he must have told the control room supervisor I was ready, control room supervisor told the shift manager I was ready, and the shift manager recommended that my certificate be signed by the manager of operations. Then I could sit on consoles all by myself.

O’Reagan: So was there an influx of younger operators at that point?

Jensen: Yes, we had quite a few coming through. My certification class, we had three supervisor candidates, and I think we had seven operator candidates. One of them ended up not completing it. All of the rest passed. Some of them, it took them a couple attempts at the eight hour and maybe even the oral board to get certified. Then right after me, there was another class with a lot of other young people. So we got a lot of young people in there, and then that allowed some of the older operators to retire. I think some of them were hanging around a little longer than they might have wanted to otherwise, just because they knew they would have been shorthanded if they left.

O’Reagan: Was this all at N Reactor?

Jensen: Yes.

O’Reagan: Was it the same training program for all the reactors?

Jensen: Well, N Reactor was the only reactor left at the time. They had similar programs at the older reactors. But it evolved over time and got a little more detailed. We had a little more stuff on reactor physics. In the original days, it’s just, this is what you’re going to do, and nobody asked why, because it was all secret. It’s just, do this and keep this needle within this range, or whatever. Later on, you actually started to teach people what was happening. Some of the old operators complained about having some reactor physics stuff in there. Wah, we don’t need this stuff. And they were so good that it’s like, I don’t know that they really did need that. They just knew what to do when something went wrong. But the theory is it never hurts to have too much knowledge.

O’Reagan: How many people were working at a given time in the actual reactor?

Jensen: In the control room, or—?

O’Reagan: That, and also—

Jensen: It’s easier for me to say in the control room, but I’ll estimate on the other.

O’Reagan: Sure.

Jensen: Minimal shift in the control room was three operators and a control room supervisor, but we generally had four. There were three positions that had to be manned 24 hours a day when the reactor was operating. One of them, the nuclear console, where you actually controlled the reactor power level, we rotated two people in and out on that: two hours on and two hours off. If you only had three, then, I think the control room supervisor could give you relief. But you weren’t allowed to be there for more than two hours at a time. The other two consoles, you could be there for the whole eight hours on a shift. After my class and the next one went through, they had enough operators that we could get six or more operators in there, which gave a lot more flexibility, both for giving breaks to people, because it can get hard to keep your focus all night long, particularly on graveyard shift, when the reactor ran itself, pretty much. You’re just looking at things to make sure everything’s normal. That gets hard to do. It doesn’t sound like it would be, but it is. It’s pretty—puts a strain on you. So we had more people to give breaks. And extra certified operators to go out throughout the plant and check things, because they could recognize problems that non-certified operators might not. So, let’s say six of us in the control room, a control room supervisor, a shift manager. They were both certified control room shift manager/operators also. So they could do anything in the control room we could. And on a typical shift, you usually had a couple of electricians, a couple of instrument technicians, three or four health physics technicians—radiological control technicians—we called them radiation monitors in those days. Plus supervisors for all of them. And maybe a handful of millwrights, pipefitters, whatever. Mostly, the maintenance people did their work when the reactor was shut down. There wasn’t very much for them to do when the reactor was operating. But there was always work for instrument technicians. They would come in, and if something wasn’t working right in the control room, we’d call them in and they would tinker with it and try to fix it. Things like that. Day shift, there were a lot more people on there. And then during a reactor outage, much more work going on, particularly or the maintenance people. Because that’s when they were tear pumps down and rebuild them and things like that. So there were probably, on days, a couple hundred people out there. On shift, maybe thirty.

O’Reagan: Mm-hmm. So you’ve sort of been doing this, but could you walk us through a day in the life? What would sort of your average day involve?

Jensen: Okay. I’d come to work in the morning, a little bit before eight. And if I were assigned to the control room, I would go in and receive a turnover from the operator whose console I was taking over. We had a schedule that rotated us through. So if you’re one or two, you’re on the nuclear console. If you’re three, you’re on the double-A console. If you’re number four, you’re on the BN console, and I do not know what BN stands for. We used to joke that it was short for boring, because it was the most boring of the three consoles when we were at full power. So if I’m going to be on the nuclear console, I’d come in and there’s an operator who’s ready to leave. He gives me a turnover, tells me what the power level is, if we’re going to be raising power, if we’re at full power, we’re just going to hold power, if there’s any areas of the reactor that seem to want to lose power or gain power. So I get the turnover and then I take over. If I was on the nuclear console, I would work for two hours, and the other operator would come in, and I would give him a turnover and he would take over. And then I would usually give breaks to the other operators, unless we had enough other people to give them breaks. Anytime you take over, you’d get a turnover for what’s going on. Worked the nuclear console for two days, then you’d go to the double-A console. The double-A console controlled the reactor pressure and the primary coolant pump speed, and sending steam to the Washington Public Power Supply System. So you had this big console, went around like this and like this, and there were separate sections for each of the steam generator cells. We had six—five operating at any one time. Occasionally we ran with four operating. We never did all six. There was a reason why; I can’t remember what the reason why was. But always had one in reserve. That one was a pretty busy console during startups and shutdowns. I had full power. It was look around, look at all of the drive turbines for the primary coolant pumps and make sure they’re running at the proper RPM, look at the pressurizer level and make sure it’s at 23 feet. Got very busy on a reactor scram—lots of stuff to do there. And after the day on the double-A console, we went to the BN console. That monitored the secondary coolant system, so we had water coming back from the Washington Public Power Supply System. We sent them steam, they sent back condensate to us. Then we had a secondary system to maintain the pressure of the main steam header. So we had to watch that, plus we had to watch the rupture monitor system, which would check the radiation levels in the coolant water outlet from the reactor tubes. There were 1,003 tubes with fuel in them. The system would compare the radiation level between two adjacent tubes, and if one of them was higher than the other, a red light would come on on this panel. Then you’d go over and push the button to reset it. They’re coming on and off all the time. But if we had a rupture, that meant there was a leak in the cladding on the fuel. Usually, it was a little small pinhole; sometimes—and I never saw this—the welded-on endcap would blow off. Uranium, normally, is not very soluble in water, but when the water’s really hot, then it’s really soluble. And we’re running at 600 degrees or so for the coolant water. So if you had a rupture, you could start dissolving the uranium very rapidly. That’s got all of the fission products in it from the uranium atoms that have split, which are highly radioactive. So you could completely contaminate the primary coolant loop. So you needed to catch a rupture before it progressed too far. That was a frustrating job because those lights are coming on and off all the time. You got to look at those, and it was kind of a bad design, because that panel was here, the other panel was over there, and you had to keep looking back and forth. So that’s why we’d call it the boring console. It was pretty boring at full power. A lot of work there, again, on a reactor startup. We had to set things up to control the main steam header pressure, and that was a lot of work. So it was kind of fun, then. But full power, it was kind of boring. After we cycled through, if we had more than four operators, then we’d have two days where we’re—you could either study, because we always had to maintain our certification, and we had quarterly requalification classes and every two years we had to recertify. Or you could just be assigned to go out in the plant and do various jobs, help out—if it’s needed somewhere, help out some of the operators who were still studying to be certified operators, help train them, things like that. And then you just kept rotating through that. If we had an outage, we only had two places manned in the control room. One was the double-A console, and the other one was the communications console. So you kept contact with everybody throughout the plant, and made PA announcements if need be. Just let people know what’s going on. If we were in charge/discharge operations, you might be assigned to work on the charge or discharge elevator, to set it up for refueling the reactor. Or just—if it’s not a charge/discharge outage or we’re already done with that, you might be going in the rod rooms and doing some valving to assist the millwrights who might be repairing control rod issues and things like that.

O’Reagan: I saw you had some pictures there. Could you walk us through some of what those are?

Jensen: Yeah. Here is a picture. I found this online in the Hanford system a while back, and I was really surprised. That’s me, and I don’t remember posing for this picture. But I am on the charge elevator here. This is the wall, and it’s opposite the reactor and it’s a shield wall and each of these things here are plugs. You can open one up on the elevator side and on the other side, there was a really large elevator called the W work elevator. It actually came off a World War II aircraft carrier for lifting airplanes up to the flight deck. They could pull a plug out there, and they would run a tube through this penetration. Then you would mate it up with the process tube in the reactor. That’s how you refueled. They must have had a photographer up there taking pictures to show other people what goes on there. That was my assignment, and so I obviously posed for this picture, but like I say, I don’t remember doing this at all.

O’Reagan: Is that your usual outfit when you were working?

Jensen: Yes. Those are called anti-C clothes, or—original Hanford terminology was SWP clothing, for Special Work Procedure.  During World War II, you didn’t want to say that this was to protect against contamination, because this is all secret what we’re doing. So you’re doing a special work procedure, so you have to wear the special work procedure clothes.

O’Reagan: So that’s a second pair of gloves there?

Jensen: Yeah. I would be wearing two pairs of coveralls, a hood, two pairs of gloves and some rubber shoes. And underneath the rubber shoes there’s some canvas booties. So this is not a real high contamination job. If we were actually refueling the reactor, I’d be wearing plastic raingear over that. We used to wear a face shield to keep water out of our face. Later on, we had a hood with a blower unit that provided air so we didn’t suffocate, and that kept water off our face. So that’s about as good as I could get on the elevator. This picture was taken of our crew in the control room. We had started a straight day shift crew. It was so we had more time for training. We worked Monday through Thursday in the control room, and every Friday we had training. And the rotating shifts, when they came in on days, they worked Friday, Saturday and Sunday in the control room, and then during the week they had training. We formed up this brand new shift. They let it out by seniority, and there weren’t that many people who wanted to do it. Some people, strangely enough, really liked shiftwork. So I managed to get on the first crew. And on our very first day working together as a crew, we had what we call a WPPSS turbine trip—the Washington Public Power Supply System bought our steam, and they had two turbines, and one of their turbines tripped. That had happened before, and the reactor had never managed to ride through that without scramming. Well, we kept the reactor from scramming. And I was on this console here—this is the nuclear console. I was controlling the reactor power level. When their turbine dropped off, the main steam header pressure goes up. This is getting a little technical, but—

O’Reagan: No, that’s great.

Jensen: The main steam pressure goes up high. That sits on top of the steam generators. When the pressure’s high, water doesn’t boil as easily. And when water boils, you get heat exchange. So we are sending hotter water back through the reactor. That is not as good a moderator as the cooler water. So the reactor power went down very fast. So I had to start pulling control rods to make up for that. In low-enriched reactors, like any of the Hanford reactors, when you lose power rapidly, you start building up a fission product called xenon which is a neutron poison. It absorbs neutrons better than anything else. At equilibrium power, we’re making xenon at a certain rate, and it’s destroyed as soon as it’s made by absorbing neutrons. So the net amount of it in the reactor is zero. But if we lose power, we’re still producing it for several hours at the old rate. But we don’t have as many neutrons in there, so the reactor power will go down and it will just make it worse. So you have to pull rods very fast. So that’s what I had to do. My part was to keep the reactor from going down so far that the xenon would take it all the way down. The other operators were working to keep the main steam header pressure from going up too high, because we had a scram trip on that, because you didn’t want to rupture the steam header. The people controlling the primary coolant loop pressure had to do work on that. It was very exciting. But we survived it, and so they took this picture as a commemoration. One of the people involved was on the nuclear console when they took the picture and he didn’t want to be in the picture. So he’s not in there. But I like this, because if you know what you’re looking at, you can actually see that the reactor’s operating. There’s some indications there that the reactor’s at its 4,000 megawatt power level. And it’s one of the few pictures I’ve ever seen where you can tell the reactor was operating. Then, almost a year later, the exact same thing happened again, and I was in the same place. It was really easy the second time, because I knew exactly what to do. So they took a picture again, for all of us. This is the double-A console. Kept these all these years. As long as I’ve got these up here, this is an aerial photo of the N Reactor complex. Let me see. This is the reactor building right here. Make sure I’m not looking at things backwards. This building over here is the Washington Public Power Supply System. You can kind of see over here there’s some lines that go over, and those are the steam lines going over to them. They bought the steam from us and then sent the condensate back after they ran it through their turbines.

O’Reagan: How much did you have to communicate with them?

Jensen: Frequently. We called them up--any time we were going to do something that might affect the power level, we would call them up, tell them we’re going to do that. If they were going to do something that might affect the condensate coming back, they would let us know. They would give us some numbers. From there, power generation, which we would compile into a daily report, I think that was the basis for how much money they paid us for the steam. Things like that. So we were in constant contact with them. Usually it was the operator on the double-A console who would communicate with the—we called them Whoops in those days. They didn’t like being called Whoops. Now it’s Energy Northwest. But that’s a habit that’s hard to break. I still want to call them Whoops. And we didn’t mean it anything derogatory in those days, but—

O’Reagan: When you said that the turbine tripped, would that seize it up? What does that involve?

Jensen: I’m not really sure why it tripped. They may have had some valves—steam admittance valves close or something. If they told us why it tripped at the time, I can’t remember. This was 1987 or so. So it was quite a while—almost 30 years ago. The second trip—not sure if it was the same cause or not. I know one time they had a turbine trip and we didn’t survive that one. [LAUGHTER] It was kind of funny. Somebody was sweeping in their control room, and the broom fell and hit a switch and caused the turbine to trip off. So on that reactor outage, they paid for everything we did to get the reactor back up. We had a special charge code. Because it was their fault, so they’re paying for it.

O’Reagan: That would, I guess, give the reactor xenon poisoning and they couldn’t start up for a certain amount of time?

Jensen: Yes. If we scrammed from full power, theoretically, you could pull control rods almost immediately and override the xenon building up. But we had a mandated one-hour hold if we scrammed from full power. And that’s so that you will make sure it wasn’t a spurious scram. If it’s something that’s actually not working correctly, so it would be unsafe to operate, you can figure that out. And by doing that—waiting that one hour, it gets impossible to start the reactor up. So our minimum downtime from full power was generally about 23 hours—23 to 24 hours. If we could figure out what the problem was and get it fixed, then we started up the next day. If I was something serious, it might take a few more days, or several days, to figure out what the problem is or correct the problem. And then when we started up, it was kind of interesting, because we had the control rods pulled almost completely out of the reactor before the reactor went critical. And then as the power goes up, you’re pushing control rods in, rather than pulling them out to raise power, until you get to a point—it’s called xenon turnaround—where you’ve burned up all of the xenon that was in the reactor, and now the reactor’s making more of the xenon and then they start coming back out. So those were actually really fun.

O’Reagan: How often did the reactor scram?

Jensen: N Reactor was getting kind of old by the time I was there. Some of the equipment was really old, old technology, and getting a little hard to maintain. We usually had two or three scrams in a particular operating run. I’m not really sure how many, because, again, it’s been so long. We would typically operate for a month. And we were in plutonium weapons-grade production mode, and so we only operated for a month, and then we would shut down and about a third of the reactor. But it was unusual to go an entire cycle without at least one scram. And usually they were spurious ones. The ones that caused a lot of them were the flow monitor system, which was a pretty old system. If somebody slammed a door or something somewhere, the instruments would vibrate, and it would give a false indication of low flow, and the reactor would scram. It only took one of the 1,003 flow monitor devices to cause a reactor scram. So that was kind of touchy there.

O’Reagan: And that was automated?

Jensen: Yeah, it was automated. You had this big panel with all these 1,003 dials. Normally, we never changed them. If we swapped steam generator cells out—like cell five was out for years until it got re-tubed, and then we put that one in and took another one out so they could re-tube that one. And we had to adjust all of those dials. Oh, that was a boring job—get them all set exactly right, and then somebody has to go through and check them all. If we ran in that mode with that same balance of steam generators, we didn’t have to do that every startup.

O’Reagan: In the pictures with the other operators, could you just tell us about one or two of the other folks you were working with?

Jensen: Okay. This is Dennis Real. Hopefully he won’t mind that I mentioned his name. He still works at Hanford. He started a little bit before me. This gentleman is Bill Terhark. He was a very, very experienced operator. He was one of the ones that you really wanted to have in the control room when things went bad, because he knew what to do all the time. He had so much experience. He went back to the 1950s, operating—probably operated at every one of the reactors. This is Fred Butcher, Jr. His dad had also been a reactor operator, Fred Butcher, Sr. And that’s me, and this is our control room supervisor, Glen Buckley.

O’Reagan: Do you know anything about their backgrounds? Were they also—I guess the one who had most experience probably trained in reactors, but were they all engineers mostly?

Jensen: No, no. Dennis had been a paramedic or EMT before he started working at the reactor. I’m not sure about Fred, what he did. Bill had graduated from high school, joined the Air Force, came out of the Air Force, got a job at Hanford. Typically, in the ‘40s and ‘50s, they did not hire engineers to be—and I don’t know what Glen’s job was—or what his background was, before. Most of us, except the older operators had college of some sort or another. When I hired on, they were hiring people usually with a couple years or more of college.

O’Reagan: So you were there through the end of N Reactor, is that right?

Jensen: Yes. In 1987—well, 1986—I think it was in April, was the Chernobyl accident. Chernobyl, although really was not similar at all to N Reactor, everybody thought it was, because both reactors are moderated by graphite instead of light-water. So everybody looked at graphite—that must be the cause of why Chernobyl blew up. Well, it blew up because it was a really poor design, and it was poorly operated, and they had a really unusual transient situation and then they had a steam explosion that tore the reactor apart. Well, we decided we would make some safety upgrades. They decided we’re going to shut down on January 7th, 1987. Six months of safety upgrades, then we’d start back up. Well, we pretty much knew we were never going to start back up again. They did do all the safety upgrades, spent millions of dollars on them, but—anyway, so we came in on January 7th knowing that this is probably the last day of operation for the reactor, and it was our job to shut it down. I was on the double-A console that day. It would have been nice if I had been on the nuclear console, to be the guy actually putting the rods in, but that was Dennis. So we shut the reactor down. Took about an hour. We still had fuel in the reactor for a good almost two years before we defueled the reactor. Because we were going to start up again. And then finally they said, no, we’re going to defuel the reactor and we’ll go on wet layup. So we still had water pumping through the pipes, keep everything wet. Because if you let it drain of water and then it’s damp in there, then things will start to rust. But if you have water flowing through there, that wouldn’t happen. So we went for a few months where we kept all of the pumps running and stuff like that, but no fuel in the reactor. And then they said, well, now we’re going to go into dry layup. So we drained the primary coolant loop and all the other systems, and then we had big fans blowing hot air through there to keep moisture from condensing in there. The thought was, maybe we’ll get the order to start up again. And then they just said, nope. Pulling the plug. Reactor is abandoned, and it’ll go into decontamination and decommissioning. And it’s essentially been torn down now, and what’s left of it—the reactor block itself—is all cocooned. Just like most of the other old reactors.

O’Reagan: What happened to your and the other reactor operators’ careers at that point?

Jensen: [SIGH] Well, that was kind of a scary time. People thought we’re going to get laid off. Some people quit and went back to school. I remember one guy went to school and got a doctor’s degree in optometry and became an optometrist. There was some programs to help people with that, some money to help people go to college and get something else. Some people just found other jobs and left. And then I ended up staying. I was getting bored with being an operator at a reactor that wasn’t operating, and there wasn’t even any fuel in the reactor. But we still had all the stored fuel, and they needed somebody to be what they called the criticality safety representative, to work with operations and with the criticality safety analyst to make sure we’re still storing that fuel safely, so we don’t have any inadvertent criticality accident. Not very likely, but it could conceivably still happen. So I got that job, and in addition to that I was doing other stuff that you would call nuclear safety work. So I ended up becoming, to all intents and purposes, a nuclear safety engineer, even though I don’t have an engineering degree. And I’ve been doing that ever since.

O’Reagan: Who is that, technically, that you were working for at that point? Was it Battelle?

Jensen: No. Initially I worked for UNC Nuclear Industries. That was UNC parts stands for United Nuclear Corporation. They had the contract to run the reactors. In those days, Rockwell ran the 200 Areas for the Tank Farms and stuff like that, and the processing plants. So they ran the PUREX Plant that was extracting plutonium from our fuel. Battelle operates the Pacific Northwest National Laboratory, and that does research and design. Right after we shut down, DoE announced that they were going to consolidate all of the contracts. Westinghouse got that contract, so I worked for Westinghouse at the time I got into nuclear safety. Westinghouse went through a contract period and then a renewal period, and DoE typically does not renew anybody’s contract—nowadays anyway—more than once. So Westinghouse left, and then they announced a bid for a new contract. The Fluor Corporation won that one, and so I worked for Fluor for several years. They went through—I think they went through two and a half. DoE gave them an extension on the second done until they could get everything in place. And then the contract was won by the CH2M Hill Company, and that’s who I work for now.

O’Reagan: Does it make much difference when one becomes—

Jensen: WE used to joke the only difference it makes is in the color of the paycheck. It makes a little bit of difference, because you get some upper management coming in, and they have different ideas on how things should be done. We all joke that we have to educate them on how things actually are done. That’s only half-joking because it’s different than anything else. Fluor had some subcontractors who had never done work for Department of Energy before. So they wanted to do things the way you do it in the commercial nuclear industry. And it’s like, you don’t get to do it that way—you do it the way DoE tells you to do it. So we kind of had to educate them. But it’s a little bit different. There’s a little bit of different philosophy every time.

O’Reagan: Was there ever any kind of either interest or communication with the commercial sector, in terms of learning or teaching any particular things?

Jensen: We did a little bit. I cannot remember the name of the organization, but it’s an organization that compiles knowledge from commercial nuclear reactors all over the country, and the disseminates that to help everybody. We had some people who would go to meetings there, so I guess we became a member of this group. I never was involved in that, but—So we would hear things that happened at other plants and then see if there were some lessons learned that we could apply. But N Reactor was so different than a commercial reactor that sometimes things that happened at N Reactor, they wouldn’t be able to use at a commercial reactor and vice versa.

O’Reagan: How secretive was your work?

Jensen: Not much. There were a few things—security stuff was classified. But what we were doing was no longer secret, hadn’t been secret since 1945. I had to have a clearance—it was a secret level clearance. Mostly that was just to make sure I was trustworthy and wouldn’t sabotage the plant or something. Very rarely did I actually see any information that was classified secret.

O’Reagan: I would assume, though, that the plutonium itself—I guess you didn’t see the plutonium until it got through the PUREX Plant?

Jensen: Yeah, well I never saw it. I’ve never seen plutonium. All of that stuff—how it was handled, how it was stored—that’s all part of the security thing, and that was all classified. And would still be, to this day, except we don’t have any plutonium at Hanford—not in any discrete form that you can do anything with, anyway.

O’Reagan: So what is it you’re doing again? Could you give us more detail on what you’re doing or what you did subsequent to being a reactor operator?

Jensen: I worked in nuclear and criticality safety for N Reactor until we shipped all of the fuel over to the fuel storage basins at the K East and K West Reactors and I moved over there. I worked in criticality safety for that. When they were storing the fuel, that was fairly easy, because they weren’t doing anything. Then they decided they needed to get the fuel out of the basins because they’re close to the river, and the K East Basin had leaked at least once and maybe twice in the past. So the contaminated water gets into the groundwater and eventually gets out to the river. So we needed to get the fuel off the river, so they built a storage facility in the 200 East Area. We had to build a whole system to take the fuel out of the basin and put it in shielded casks and ship it over thee. So there was a lot of work on that, and all of that had to be set up to prevent criticalities. And also nuclear safety, which is more concerned with releases of radiological stuff to the atmosphere. So you need to keep those releases down below certain guidelines that DoE provides to protect the public.

O’Reagan: So was this at all part of this amelioration cleanup efforts at that point?

Jensen: Yeah, that’s the whole goal that we’re working towards: get all of the fuel out of the reactor basins. So we got it all out of the K East Basin first, and then that’s actually been destroyed—the basin has been completely dug up and destroyed, and the area backfilled. The reactor’s prepared for cocooning, but hasn’t been, because they ran out of funding. So it’s in a safe, stable condition right now. K West Basin is empty of fuel, but it has sludge. I still do some work for 100 K, although mostly I work at the Plutonium Finishing Plant now. They’re going to move all the sludge out, and then they’ll do the same thing to the K West Basin that they did at K East. And basically, all over Hanford, that’s what they’re doing is cleaning things out, and getting them ready for demolition. So I work at PFP now in nuclear criticality safety there, and they’ve got miles and miles of ductwork. Some big pipes and some little pipes that are all contaminated with plutonium, and they have to carefully take all that stuff out. Get enough of that out so they can actually start tearing the building down.

O’Reagan: Are there any general ways, whether it’s the type of people working there, or morale, or whatever, that the work at the Hanford site has changed over the time you’ve been there?

Jensen: [SIGH] During the operating days, it was fun. Actually fun to go to work and do something that you thought was productive. I mean, you can argue whether you thought we should have been making plutonium for nuclear weapons or not, but the job was very interesting. When the reactor shut down, the morale went down quite a bit, because, for one, people thought they were going to lose their jobs, and two, it’s like, well, even if we stay here for decommissioning, that’s not going to be anywhere near as interesting. And it isn’t. It has its own interesting aspects to it. But mostly, people are pretty professional and here’s a job, we’re going to get all of the fuel out of K East. So people went and worked on that, and we’re going to get all the fuel out of K West, so you work on that. While you’re doing that, it’s satisfying, because you’ve got a goal to work for. PFP—it’s a very difficult job. I think the morale kind of goes up and down. We have successes and then there’s problems you run into. But in a way that’s what makes a job interesting, if there’s problems that you can resolve and get through it, and then you succeed on this task and go onto the next one. But it was a lot more fun to operate than to do what we’re doing now.

O’Reagan: How much longer would you guess we’re going to be doing this--?

Jensen: I, personally, or Hanford?

O’Reagan: Both, why not?

Jensen: Well, PFP is supposed to be torn down. It was supposed to be torn down by the end of September this year, but it’s probably going to be about a year off from that. The K Basin—K West Basin has sludge in it. They’re probably going to start removing the sludge in about two years. That’ll probably take about a year to do that and then they’ll start tearing that basin down. There’s still a huge project called Groundwater, where they’re pumping contaminated water, and it’s not just radioactive contamination, there’s a lot of heavy metal contamination in Groundwater. They pump that out, and they run it through processes to take the, like, chromium out of the water and replace it with a type of chromium that’s not as environmentally damaging. That’ll go on for years and years. And then there’s still—all of the old processing canyons are still there in place, and all of those are going to have to be torn down at some point. So, it’s probably decades more work here. And then there’s all the tanks. They’re going to take all the waste out of the tanks and run it through the Vit Plant which isn’t done yet. So years of work left at Hanford.

O’Reagan: Interesting. Were you ever interested in the sort of politics of Hanford?

Jensen: Not too much. The politics were different. In the ‘80s, it was whether we should be making weapons-grade plutonium or not. Nowadays the politics is more like, which project do we rob from to give to somebody else? And political battles in Congress as to how much funding Hanford gets, and things like that. So I try and stay out of all of that.

O’Reagan: Sure. So how about life outside of the work plant? Where were you living—still in Kennewick?

Jensen: Yes, I’ve been living in Kennewick since I moved there as a kid in 1965.

O’Reagan: Where in Kennewick?

Jensen: It’s over near Highway 395 as it kind of cuts through the middle of Kennewick.

O’Reagan: How has life in the Tri-Cities changed in the time you’ve—

Jensen: The Tri-Cities is a lot bigger. It was pretty small when I first moved here. For several years, it was just slowly growing, and it’s been growing like crazy since. It’s like, they’re always building new schools, and there’s always housing developments under construction. There used to be a lot of orchards in Kennewick, all around. There’s hardly anything now, because they’ve all been cut down and there’s houses there now. Traffic’s a lot worse.

O’Reagan: What do you do in your spare time? Any hobbies or--?

Jensen: I like photography, I like to take pictures with film, which is old-fashioned nowadays. And I like to develop the film myself. So far that’s all been black and white film; I haven’t tried developing color film yet. And I like to collect old film cameras that I can still find film for and use those. Up until recently, I was playing hockey—adult hockey, which I started when I was 49, started playing hockey. I’m 60 now, so I’ve been doing that for about 11 years. However, I had quit, hopefully only temporarily because I’ve got some medical issues. My doctor said no hockey until this is resolved. And then I hurt my knee the other day, so I don’t know. That might—even if the other one gets resolved, that might be the end of hockey. I like to go to Tri-City Americans hockey games during the season. I got to Tri-City Dust Devil games during the baseball season. Like to go to plays and movies. I decided this year I was going to audition for a play, see if I could get in. I did not make it, but I’m going to try again, coming up later. Probably this summer. So we’ll see. Never done that before, either. But it always sounded like fun.

O’Reagan: Any sort of major events or incidents, whether at work or just sort of around the Tri-Cities that comes to mind that are sort of worth commemorating, or worth just sort of mentioning?

Jensen: Kind of the interesting thing—back in 1986, reactor was still operating, and do you remember Connie Chung, the news—she came to the Tri-Cities to do a show on Hanford. Everybody at work was wondering who she’s going to interview. And we’re thinking they’re going to interview, like company president, company vice president, or something. And I remember joking that she should interview a reactor operator like me. And everybody laughed. And about an hour later, the phone rang, and it was the producer wanting to talk to me, and they wanted to interview me that night. And I got permission from the company. Turned out, my dad, who, like I said, had worked at the Tank Farms—he had gone to a public hearing on what to do with tank wastes. The Connie Chung crew had gone to the same meeting, because they were getting background information. My dad spoke at the meeting, and they said, oh, we have to interview that guy. When they talked to him, he mentioned that his son worked as a reactor operator. Oh, god, that’d be great, interview them both. So that’s how I got called up. The company gave me permission, and they did it in my house. I told them, it was my son’s third birthday, and I said we’re going to have a birthday party, but you can do the interview after the birthday party. So they said okay. After I got home, my wife sent me out to buy ice cream, I think. And I’m coming back. When she came back, she was all excited. Connie Chung called personally and asked if they could film the birthday party. So they filmed my son’s third birthday party, and then they interviewed my dad and I in my living room, and then—I don’t know, two, three hours of interview stuff, and they boil it all down to about five minutes. But that’s the way that goes. So that was kind of exciting. I was a minor celebrity for a while.

O’Reagan: Any other stories leap to mind?

Jensen: We had some interesting scrams in the control room. I talked about the two turbine trip ones that were very interesting. The first one, like I said, I had to pull control rods rapidly to compensate for the xenon building up faster than it’s being burned out. I got that all settled out, and the power level wasn’t dropping, and I had forgotten that--when the main steam header pressure goes up, the power level goes down—well, eventually, they’re going to control the main steam header, and it’s going to go back where it’s supposed to be. And the power all of the sudden starts shooting up. So now I’m shoving control rods in like crazy to keep the power level from going up too fast, because we could scram on a high rate of rise. So I got that all settled out. The second time it happened—since I was the most experienced person on the plant on this upset, I got it settled out from the xenon, and I just got my ear open over here, and as soon as I hear somebody say, main steam header pressure’s coming down, I look over and the power level starts to go up, and I tap some rods in, and it was just like routine. Nothing to it. But another time, we had another accident—well, accident’s probably not the right word. We had another upset. We had a new control system—computerized system for controlling valve positioning. The old system we had was very ancient. It was obsolete when they put it in at the reactor, but they got a good price on it, so that’s why they did that. So we had this new computerized system, and there were two cards in the computer that controlled the valve positioning. The primary card, and a backup card. If the primary card failed, you would transfer to the backup card, and it was supposedly a bump-less transfer. The system wouldn’t even know. The primary card had failed, and so it transferred to the backup card, and everything went perfect. Well, the instrument technicians took the primary card out to repair it, and they came to put it back in. Now, this card controlled the steam valves going over to WPPSS. I was on the console controlling all of that, and I remember, jokingly, I said to the guy—the instrument tech and the engineer, when they came in, they were going to go to the rom below the control room where all of that stuff was. They were going to replace it, and I said, you aren’t going to scram us, are you? And the engineer said, trust me. And they went down—and I was just joking, because I figured, no big deal—and they went down and they put the primary card in and they told it to take over. It took over and sent its signal to the valves, but the secondary card did not relinquish control. So all of the steam valves opened up twice as far as they were supposed to. So our steam pressure goes down, and when that goes down, the reactor power goes up. And the primary coolant pressure also goes down, because you’re boiling water really well in the secondary system, that cools the water really well in the primary system, and cold water contracts. So that pressure goes down, and if the pressure goes down to far, the reactor scrams. So I’m fighting like mad with—somebody else came over to help me—to keep from scramming on low pressure. Other people are working over here, trying to keep from scramming on something over here. And other people over here, and the guy on the nuclear console is trying to keep the power level from going up too fast. We’re running around—it was very exciting. Seemed like it took hours. Probably just took a few minutes. We got it all stabilized out, and I’m looking at the primary loop pressure, and it’s kind of fluctuating and bouncing. And right when it’s going—trying to think if it was going up or down. See, if we cool—it had to have been going up. The secondary card cut out, all the valves slammed shut, and we had the exact opposite thing happen. Now, the primary loop gets hot, everything expands, and we scrammed on high pressure. And then about five minutes later, the instrument tech and the engineer come upstairs. They could tell something bad was happening, and they just looked like—it wasn’t their fault, but—

O’Reagan: When it actually does scram, is it actually just rods, or—I’ve heard some designs where there’s actually just balls that are—

Jensen: Okay. The main system was control rods. And you were going like this, like dropping down from the top. The old reactors had safety rods that dropped in from the top. N Reactor’s rods all came from both sides, and they overlapped. All the rods would slam in with hydraulic pressure. We had some hydraulic pumps that would turn on and pump very high pressure hydraulic fluid into the system, and the rods would shoot in. It would take about a second-and-a-half to go in. And you’d get all these enunciators in the control room, and if you were—mmm, it’s pretty boring here at two in the morning, and then all of the sudden the reactor scrams, you were wide awake. Got adrenaline pumping through and then you’ve got all these things you have to do to make sure everything works correctly on a scram, because it causes all kinds of things. The balls were the backup to the control rods. They had to be 75% in in one-and-a-half seconds. If they went in too slow, there was a problem. If they went in too fast, there was a problem, just because they could be damaged. But if they went in too slow, that’s what the ball system was for. There were hoppers on top of the reactor—I think there were a hundred-and-some reactors. And they were full of boron carbide balls. Boron absorbs neutrons. That’s what’s in the control rods to absorb neutrons. If you had one slow rod, it’s no big deal. If you had two slow rods in one column, you would drop balls on both sides of that rod column. If you had three slow rods anywhere in the reactor, you would drop balls on both sides of each of those three rod columns. Then there was also a thing where you could have a complete ball drop—drop all of the balls. If the reactor power level did not decay below five megawatts in three minutes, I think it was, then you would have a complete ball drop. That happened twice. Once, for real, because we had a scram and the rods didn’t go in at all—this is before I started working there. So there’s a scram trip, the rods did not go in, the balls dropped. And the other one was we were starting the reactor up—getting ready to start the reactor up and going through all of these checks on various instrumentation. The instrumentation that would monitor if the reactor power was below five megawatts in three minutes, they were doing the work on that, and they had a procedure that they would run. There were three channels and they would run it on each channel. That included having a switch to put in a couple of different calibrate positions. Basically, it put a false signal into the system so you could see if it’s responding correctly. So an operator and an instrument tech were doing that. They did channel one and it didn’t look right when they put it in the calibrate position. So they went on to channel two to see if it would do the same thing, and they did that. Well, they put two trips into the system. The reactor—what we called the safety circuit—was not made up, and so the system started timing for five minutes. These two instruments said the power level was greater than five megawatts with the safety circuit broken. When the give minutes went up, all the balls dropped. It was kind of innocuous. There was an enunciator that said, any ball hopper open. So the enunciator goes off, and the operator looks up at that. Any ball hopper open. And then he realized what happened. He told the control room supervisor, and the control room supervisor told me that. He says, I looked up at it. And I looked down. And I looked up again to make sure it was actually on. And then he said a few bad words and then he went and told the shift manager that we had dropped all of the balls.

O’Reagan: I heard on the old reactor designs, that had to be actually sort of vacuumed out.

Jensen: Yes. They used vacuum—they were steel balls, too. And they used vacuums to suck them up. At N Reactor, we had a valve at the bottom of the channel that you would open up, and the balls would drain into a hoist, and then you would lift them all the way up to the top, and put them in a hopper at the top—a big hopper—and then you would load the individual hoppers. That was a horrible, horrible job, being up there loading those hoppers. It was always hot, you had to wear plastic raingear and an assault mask, which—rubber hugging your face, and it’s hard, physical labor, and wearing the raingear and it’s already 100 degrees up there anyway. It was just miserable work. So nobody liked to do that. When we had that big ball drop, my job was to go down underneath the reactor. You could open up those drain valves remotely. So we had Bill here who smoked a lot and was not allowed to wear respirators, he was operating the control panel. But a lot of times, the valves wouldn’t work remotely. So, me, wearing all of this fresh air stuff, would stand by, but would say, 43 didn’t work. So I would have to go back there, trailing this hose with my fresh air, and go back to 43, and open it manually. It was extremely hot, radioactively, down there. I picked up my entire one week’s worth of radiation. We were allowed 300 millirem of radiation, either in a single exposure or in a seven-day period, and I picked up that entire 300 in less than an hour, going back and forth. And most of the time, I was just standing there, waiting. And I’d go back in there, and I’d pick up quite a bit, and I’d open up a valve and come back, and then I was done and left. Couldn’t work in a radiation zone for seven days after that.

O’Reagan: How often did you have the radiation testing? Or was it the hand-and-foot test—

Jensen: Oh, any time we came out of a contaminated zone, contaminated area, when we were wearing those SWPs, you have to undress in a proper sequence. I don’t know if you’ve ever seen this. We had step-off pads. A red pad and a green pad. And when you get to the red pad, before you get to that, you have to remove all of your outer clothing before you step on the red pad. And then when you get to the green pad, you have to remove all of your SWP clothing before you step on the green pads. So you end up coming out there—well, in the old days when there were very few women working in the Area, you’d be coming out in your underwear. Later on they made us wear a t-shirt and shorts. But I kind of lost track of what we were saying there. Oh, the hand-and-foot counters. And then when you came out, we would step into a hand-and-foot counter or a whole-body portal monitor that would monitor our sides and front and back, to make sure we weren’t contaminated. Then usually we would also be surveyed by a health physics technician who’s got a Geiger counter, and he just slowly goes over, checks your hands, checks the bottom of your shoes, makes sure you’re not—don’t have any skin or clothing contamination. If you do, then you’ve got to get decontaminated. And that happens once in a while.

O’Reagan: Was that ever a concern of yours?

Jensen: No. I did get a few skin contaminations. I had to hold over once. I got some primary coolant water in my hair, and there was a lot of radon in the water. Radon is electrostatically attracted to polyester and hair. So it latches on, and it’s hard to get off. I just had to wait until it decayed off. After about--

O’Reagan: Did you shave?

Jensen: No, no. I washed my hair several times, and then they just said—come back every hour and we’ll check, and after about three hours they let me go home. Usually, skin contaminations wash off pretty easy. If it’s your clothing, you have to wash the clothing. You don’t get to take that home until it’s passed as clean. Sometimes, rarely, stuff would have to get thrown away. But I never had any serious contamination issues. If you’re careful, if you dress correctly, and then when you come out, you undress correctly, then it’s very rare to be contaminated.

O’Reagan: Any other sort of stories leap to mind from your--?

Jensen: There’s a few things that happened before I was there that were interesting. I don’t know. We had an accident. It was about three—and this one is an accident—it was about three years before I started work. They flushed a tube of hot, radioactive fuel onto the charge elevator, which is not where it’s supposed to go. It’s supposed to go out the back, and fall into the discharge shoots and then go into the basin. There were workers on the elevator when it happened. They got very high radiation exposures. Fortunately, not high enough to kill anybody. But that was just lucky, I think. So, I don’t know. That was the most serious thing I know that happened there. We did have one—before I was certified, we had one really bad accident where we lost all the instrument air to the plant. Almost every valve functions with air—they’re air-operated: air to open, air to close. A lot of pumps are—the pump speeds are maintained by air pressure, things like that. So we had a scram, and it was a very abnormal scram. But we survived it.


Camera man: Okay, hold it out so we see.

Jensen: --piece of fuel out of the reactor, and they pushed all the hot, irradiated fuel out, but we’d done a normal refueling after that shutdown. And, well, now, we’ve got to—we pushed out all the hot fuel, and now we’re going to push out all the un-irradiated fuel and keep it, just in case we start up again. I happened to be walking by when they got the last one out, and they were taking a picture and they said, get over here!

Camera man: Oh, so where are you? Are you down in front there?

Jensen: I am right there.

Camera man: Yep, that’s right.

O’Reagan: You’ve got the [INAUDIBLE] gear guy in back.

Jensen: So these guys are all dressed up in the gear and they’ve got the fuel with them. I think they’ve got the fuel with them in there. There’s another picture that I don’t have that actually shows them holding the last piece. [VIDEO CUTS] There were two certified operators when I was hired on. I think there had been some more who had left. There was another lady who was in the certification program and then she certified shortly after that. In my class, there was one woman and she did not go all the way through, and then in the class after, there was at least one woman in there. So we had a handful of women certified operators. The very first one hired, I’m pretty sure that would have been Martha Coop. I’m wondering who the guy you talked to was who hired her. Because I’m sure I would know him. I just can’t think of who that might have been. The other one was Leslie Jensen, no relation to me, and I think she was the one who babysat me when I was probably a kindergartener or a first grader. She was one of my mom’s students.

O’Reagan: All right. Anything else I should be asking here, any other memories that are worth preserving?

Jensen: I’ll probably think things when I get home.

O’Reagan: Sure.

Jensen: But right now I think I’m—

O’Reagan: Great. All right, well that’s been great. Thank you so much for being here.

Jensen: You’re welcome.

View interview on Youtube.



Bit Rate/Frequency

317 kbps

Hanford Sites

N Reactor
200 Area
Tank Farms
WPPSS (Washington Public Power Supply Systems)
UNC (United Nuclear Corporations)
PNNL (Pacific Northwest National Laboratory)
K East Reactor
K West Reactor
K East/West Basins
PFP (Plutonium Finishing Plant)

Years in Tri-Cities Area





Hanford Oral History Project at Washington State University Tri-Cities, “Interview with Mark Jensen,” Hanford History Project, accessed March 21, 2023,