Keeping T ave in the Green Band


Cruising around the Pacific – under the Pacific, more specifically – in a nuclear-powered ballistic missile-carrying death machine sounds terribly exciting. It mostly isn’t.

On the USS Sam Houston (SSBN-609, Gold crew), our primary mission was to remain undetected and that didn’t allow for a lot of noisy charging around the ocean playing war games and such. We pretty much just set the cruise control to a few knots (clarification: there was no cruise control) and waited until called upon to annihilate a few cities and subsequently get nuked ourselves (launching missiles and remaining undetected are similarly incompatible activities). Sure, we’d regularly do drills to keep our game up – a lot of drills if we expected an ORSE when we got back in from patrol – but there was often a lot of routine time when on watch. And there were ship’s evolutions that interrupted routine: battle stations missile drill, casualty drills, field day, to name a few.

Mind you, I’m talking about watch-standing, where you have a specific station with specific duties to perform. When on watch, you didn’t do anything else other than watch-standing stuff. Non-watchstanders did everything else that needed to be done, which for us in the engineering department meant routine maintenance and repairs on our equipment. Off watch also was the time when you worked on your qualifications, your quals. Depending on your rating, you had different things you were expected to qualify for – watch stations, basically. And everybody on the boat had to qualify in submarines, earn their dolphins. All that took up a lot of your off watch hours. Whatever was left over was for eating, personal hygiene and sleep.  Especially sleep, the rarest, most prized of luxuries on a sub.

The mid-watch, between midnight and six, was the quietest time. I should mention here that time of day was a pretty weird concept on a submarine, for two reasons. The first is obvious: we didn’t see the sun from the time we left port to when we returned and there was no external effect that can be noticed while underway. It’s not like some characteristic of the ocean changed through the day. Submerged at patrol depth was same at noon as at midnight. Clocks were all we had, and frankly, that’s enough. It’s not that difficult to keep a rhythm with your body using just clocks, as long as the clocks were keeping time as normal. But the second reason was far more disturbing to your natural rhythms. Most people on the sub were on a three-man watch rotation and watches were six hours long. So your ‘day’ effectively was eighteen hours long. I’m here to tell you, that will fuck with your mind and body in ways you can’t expect. You get somewhat used to it, but never entirely. A couple of months at sea on that schedule also makes for an interesting time when you come back to port and go back to 24-hour days. But the boat itself stayed on a 24-hour schedule in terms of meals, which were the most tangible indicator of time of day, other than clocks. We had breakfast at 6 AM, lunch at noon, dinner at 6 PM and ‘mid-rats’ at midnight. Mid-rats (short for midnight rations) was typically leftovers or cold cut sandwiches. You ate before going on watch and immediately after.

After having been on the boat for a couple of patrols and completed my quals, my watch station normally was in maneuvering.  Maneuvering was the engineering control room where the reactor, main engines and electric plant were controlled. Four people were always on watch: the throttleman who was responsible for the main engines and thus the speed of the sub, the electrical operator who maintained the boat’s electrical power by controlling two steam turbine generators, two motor-generators sets and the battery, and the reactor operator who kept the reactor where it needed to be to provide steam power to the engines and TGs. The fourth guy was the EOOW, engineering officer of the watch, who didn’t have much of anything to do except keep the other three guys in line. I was a reactor operator.

The Smithsonian has a replica of a submarine maneuvering room similar to that on the Sam Houston. Throttles on the left, the RPCP (Reactor Plant Control Panel) in the middle, the EPCP (Electrical Plant Control Panel) on the right. The EOOW would sit in a higher chair overlooking the operators from behind. It was a cozy space. You can find photos of real maneuvering rooms which show it better but due to recent chatter on submarine forums about people getting in trouble by publishing photographs of classified areas, I’m not going to post any here. The entire engineering spaces on a US nuclear submarine were, and still are, classified areas.


Here’s the thing about pressurized water reactor power plants: if power demand is stable, such as when the Conn hasn’t ordered a change in speed for a while, and nothing else is going on, the plant tends to be pretty static. Temperatures and pressures don’t change and we really don’t have much to do other than take log readings every hour (Full disclosure: when the plant wasn’t changing, we often didn’t take logs every hour, completely in violation of regulations). About the only thing I had to do was occasionally bump the control rods to keep the average reactor primary temperature (T ave) in the ‘green band’. It would slowly drift down due to a couple of reactor physics factors, even if power demand was steady.

The reactor was actually self-regulating. If the throttleman opened up the throttles, allowing more steam to the main engines, reactor primary inlet temperature would drop a bit which increased the reactivity in the core, which increased reactor power, which then increased primary outlet temperature until a new equilibrium was reached. The two temperatures which made up T ave – T cold (reactor inlet temp) and T hot (reactor outlet temp)- would be further apart, a greater delta temperature across the core with the average still in the green band. When the throttles were opened (or closed), my job was to anticipate the power demand and adjust the control rods to keep T ave in the green band while the reactor settled itself out. I might also have to shift the main coolant pumps to fast speed if power demand exceeded that which slow speed could accommodate. If for some reason the Conn ordered a big increase in speed – say going from ahead one third to ahead flank – and if the three maneuvering operators had their shit together, you’d see a choreographed set of actions. The throttleman would whip the  throttle wheel open as fast as he could, the electrical operator would simultaneously start cranking up the TG speed in anticipation of the reactor operator switching to fast speed pumps, which required quite a bit more electrical power. After the pump switch, which happened in seconds, I’d grab the control rod shim switch and start pulling out the control group, also anticipating the power demand and keeping T ave from dropping too much out of the green band. After the main engines were up to speed, we’d then start backing off on the TGs and the rods to avoid overshoot. It would be like two minutes of excitement. That didn’t happen very often while we were on patrol status because a rapid increase in propeller shaft speed would cause cavitation, which is noisy. The Russians might hear us and we couldn’t have that.

Mid watch, then. Not much going on. Being rebellious young men who were easily bored, sitting in the maneuvering room watching the gauges not move tended to be inadequate entertainment and the EOOW often failed miserably in his primary duty of keeping us in line. Hell, the EOOW was bored, too. So we’d do things to amuse ourselves. Some of those things weren’t actually in keeping with regulation and good watch-standing decorum. For example, if the EOOW was a junior officer and thus subject to being fucked with, a couple of us might simulate loud gay sex. Or all three of us. Said junior officer would suffer a bit of apoplexy but would eventually realize what was going on. I’d say unlike some of the non-nuke officers (you had to be a nuke to stand any watch in engineering, including EOOW), the nukes were almost universally regular guys and we got on well with them.

The reactor operators in particular, but also the maneuvering room operators, had a bit of a tradition dating back to the sixties when the boat was first commissioned. During mid-watch, we liked to remove the lamicoid labels from the RPCP and write nuggets of anti-navy wisdom on the back. There were a lot of labels and because they were attached only by small screws, taking them off was easy. Sometimes we’d get a little carried away and the RPCP would briefly look inoperable what with all the parts removed. Reading things written by people from years past felt semi-religious, like you were reading ancient scrolls. A few of the labels were quite big so one could write a lot. By the time I was on the boat (late ’70s), not much writing space was left but I managed a few tidbits of my own. Mind you, we had to be sure the captain or other intruder didn’t pop in for an unannounced visit, so we had a system whereby the AMR2UL watch would warn us if he came through. If we had the panel taken apart too much, we’d have been screwed as it only took twenty seconds or so to make your way from the forward part of AMR2UL to maneuvering.

Later in my time on the Sam Houston, I got so bored that I took to welcoming drills during watch. Casualty procedures were not all that complicated or extensive, so once you knew them and gained confidence, there wasn’t the previous dread of a drill where you might fuck up. Fast scram recoveries in particular  were actually fun. They say that navy nuclear reactors are hot rods as compared to the bigger, much less flexible commercial power reactors and it’s true. A fast scram recovery was like drag racing. Imagine taking control of a nuclear reactor that just unexpectedly scrammed (shut down) and bringing it back up to power as fast as you could. The idea is that in a battle situation – or worse, if the boat is sinking – you need to keep the main engines on line so you maintain forward speed. The turbines drew steam at such a rate that the reactor’s primary system cooled pretty rapidly and would be too cool to produce useful steam in short order. So the reactor had to come back to power quickly. We even had a ‘battle short’ switch that would disable all reactor protection functions, including whatever might have caused the scram in the first place. Better risking a damaged reactor than having the boat sink. Battle short wasn’t used during drills.

During my last patrol when I was the senior reactor operator, I volunteered to qualify for the machinist mates’s watch in AMR2LL. M division was short-handed, unlike us reactor operators, and were having to stand port and starboard watches there. That’s six hours on watch, six off. Very grueling. But I also wanted to do it because the emergency diesel generator was in AMR2LL and it was cool to operate that beast. Plus, the steam generator sampling station was there, so I got to play with chemicals. The steam generators were the boilers that transferred primary system heat to the secondary steam system for the turbines. Because of the metallurgy involved, it was important for the water chemistry in the SG’s to be maintained within tight limits. AMR2LL watch would periodically draw a sample, test it for pH and a couple of other things and then add chemicals to adjust the balance. Much more fun than keeping T ave in the green band.

Despite what I’ve written here, my time on the submarine wasn’t just boredom laced with periodic bursts of drag racing excitement and some mad chemistry. It was frankly a miserable experience all told, which is why I got out of the navy as soon as I could. But that’s another story. I made six deterrent patrols on the Sam Houston in all. That was enough. I still have dreams about being on the boat – having to make one more patrol.

Shortly after I left the boat it was converted to a ‘slow attack’ and had its missiles removed to comply with one of the SALT treaties. The Sam Houston was re-designated as SSN-609 and operated as a SEAL insertion vessel for a while before being deactivated and struck from the rolls active ships. It was dismantled and scrapped in 1992. The reactor compartment is now in a disposal area at Hanford Nuclear site in Washington state.

4 thoughts on “Keeping T ave in the Green Band

    • Operational Reactor Safeguards Examination. It’s a rather grueling examination of how well the boat is complying with navy regulations in operating the reactor. The boat picks up several officers from Naval Reactors (the reactor regulatory group within the navy) at the end of patrol and then goes back out and submits to whatever evil drills and tests the NR team has in mind. Failing an ORSE is a serious black mark on the captain’s record, so there was great pressure to perform well.


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