tag:blogger.com,1999:blog-26580129.post8876308747025067104..comments2024-02-04T02:12:39.772-08:00Comments on Spud's blog: Odd Quirks About Nuclear Reactors - Xenon and Decay HeatMarkhttp://www.blogger.com/profile/02966009363351648139noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-26580129.post-47564044411589614362019-11-02T09:02:24.575-07:002019-11-02T09:02:24.575-07:00Cool story. Thanks.Cool story. Thanks.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-26580129.post-90362502833466135012019-10-26T09:17:37.295-07:002019-10-26T09:17:37.295-07:00LOL @ those stories. Brings it all back home, does...LOL @ those stories. Brings it all back home, doesn't it? Thanks for sharing those!<br /><br />This is my ship's contribution to the S5W/S3G RPM revision table.<br /><br />We were doing a weekly op with our Prospective CO on board, who was about to take command of the ship.<br /><br />One of the little MSSV bypass valves had a packing leak. Maybe to show off to the PCO how awesome our engineering department was, we went single loop, cooled down the loop, and replaced the packing while underway.<br /><br />Unfortunately the watch-stander situation in maneuvering was grim. We had a green EOOW and Throttleman, a very short-timer RO, and an EO (me) who was disgusted with everything Navy. The AMSUL asked if he could start the weekly Trip Point and Calibration Check. Two people in maneuvering didn't know any better, and two people DGAF. The EOOW told him to go ahead with it.<br /><br />When the AMSUL took the MCCVs on the only operating loop to test, the reactor scrammed. Of course.<br /><br />We sat there for a couple of minutes with the poles in the holes and had a brief discussion about a FSRU: <br />Cause known and corrected? Yes! <br />Elapsed time < X hours? Yes! <br />Tave > XX degrees? Yes!<br /><br />Then the EOOW asked the big question: "Can we do a FSRU while in single loop?" The RO just shrugged his shoulders and said "The RPM doesn't that you can't"<br /><br />"Very well then, commence a FSRU." "Commence a FSRU, Aye" Away we went. We were 90% finished and right at POAH, when the PCO wandered by. His eyes bugged out and he told the RO directly to scram the reactor right now. RO shrugged his shoulders again (he *really* DGAF about anything but EAOS at that point), got up and announced "Scramming the reactor".<br /><br />Then we all got relieved from watch and green tabled. Meanwhile our reliefs had to do a full precrit and normal start-up while we bobbed around at PD for another hour, LOL. I often wonder what the PCO thought about *that*<br /><br />A couple of months later, an RPM revision came out stating that it is not permitted to perform a FSRU in single loop, because accident modeling for such a scenario has never been performed. Heh. Markhttps://www.blogger.com/profile/02966009363351648139noreply@blogger.comtag:blogger.com,1999:blog-26580129.post-32981315389235381122019-10-25T09:14:28.333-07:002019-10-25T09:14:28.333-07:001. Love to hear the other 'tractor story. Yo...<br />1. Love to hear the other 'tractor story. You the man!<br /><br />2. Yeah, we picked up the rod after a long day/night. Just harsh because of being in warm water on DG. No AC. You're ventilating, but still sucks. Gets real hot in the ER, given you still have steam headers and such. 145F between the main engines (close to burn temps)...ERUL would just take his logs and move on...ASAP. But whole boat was well above 100F. I think the bow compartment was cool. (Like 100ish.) Effing coners. ;-) We deviated from reduced electrical to keep the ice machine operating as watchstanders needed it--helped a lot, lower core temp.<br /><br />3. Funny story about specop and losing some crypto keymat (TS of course). Whole boat was searched. No find. But we had been saving trash after all. So they put down plastic on the mess deck tables and opened the cans and searched them. It was in 57th of 63 cans. (Was more icky than the shellback ceremony's slime.)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-26580129.post-51198878370987477012019-10-24T09:10:54.942-07:002019-10-24T09:10:54.942-07:00That's very dangerous. Glad you got the DG goi...That's very dangerous. Glad you got the DG going. Must have been wild just bobbing around, not even an EPM.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-26580129.post-23014213192501287032019-10-21T19:56:50.774-07:002019-10-21T19:56:50.774-07:00Dayam! Those are awesome stories! Thanks for tho...Dayam! Those are awesome stories! Thanks for those.<br /><br />You guys must be the reason that the XC lineup always got secured once we were out of the harbor :-) That CWA must have been crazy! I would imagine not only inspecting the XC HX, but also some serious inspections of the areas that experienced the biggest temperature shocks. That's awesome that the RO was able to keep it under control without giving up and scramming. Sincere props to the guy! <br /><br />Regarding the dropped rod, were you able to grab it again, or did you have to limp home at a 1/3 bell and get assistance from a facility? <br /><br />We had one incident (before I arrived on board) where they nearly lost the ship. Shortly after a battery change-out, the ship went to sea. During a reactor scram drill, after both SSTGs were offline, the main battery disconnect melted. Complete loss of all AC and DC power. They surfaced in rough water and initiated XC. Couldn't establish radio comms with the hand-held devices. Kept spilling air out of the MBTs and having to puff them from the air banks. They had depleted 3/5 air banks before getting the diesel gen to fire, and flashing the field using 20 or so emergency light batteries wired in series. It was a close call. <br /><br />I have another really funny reactor story if you are interested.<br /><br />Markhttps://www.blogger.com/profile/02966009363351648139noreply@blogger.comtag:blogger.com,1999:blog-26580129.post-90358869090230619792019-10-21T12:57:04.988-07:002019-10-21T12:57:04.988-07:00No worries. I actually sorta loved it, even at th...No worries. I actually sorta loved it, even at the time. The whole quixotic saltiness of it. <br /><br />Remember my NR engineer's exam and the guy is asking me the broken vacuum injured man in the RC question. I told him..."well I had an injured man in the RC a couple weeks ago...60 stitches and an ambulance". He just looked at me in amazement like it was all stuff in a book to him. I told him I was from the "cursed boat". He looked down at the name..."oh yeah, that one".<br /><br />We literally (and not how millenials use that word) had the worst safety record in the nuclear fleet. Average sub ran 3-4 incidents a year. We were doing 12 minimum. Lots of "help from squadron" and lots of disquals, LOIs, etc. It was painful.<br /><br />But GREAT sea stories for giving training on the next boat, talking about the usetaboat. OK...let me tell you about BOTH times we inadvertently initiated XC. Once at power (it's a cold water accident...power did increase, and at a limiting bell...RO shimmed in to control). And once in port. You gotta go in afterwards into the tank and make sure you didn't fry too many barnacles on the walls...not kidding. Dropped rod...been there done it...and on specop...what a pain the ass...thousands of miles from another US asset. We were cursed. But, well...good stories.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-26580129.post-64020725480526710052019-10-21T00:32:17.588-07:002019-10-21T00:32:17.588-07:00Thanks for the great comment.
Interesting (but ...Thanks for the great comment.<br /> <br />Interesting (but not surprising after giving it a little thought) that the decay heat was fiercer on a very old core. You had built up lots of transuranics and fission products in there, without a doubt, compared to a fresh core. Don't think I'd enjoy going to sea on a boat that had such a sketchy power source, but we do what we're told, yes? <br /><br />Also not too surprising that it would take a LOT of rod motion to get any kind of reactivity out of old fuel. I suppose it would be pretty sluggish in either direction.<br /><br />Again, thanks for the excellent comment and for sharing that experience!Markhttps://www.blogger.com/profile/02966009363351648139noreply@blogger.comtag:blogger.com,1999:blog-26580129.post-55515127685324206602019-10-18T23:45:05.492-07:002019-10-18T23:45:05.492-07:00Was on an S5W reactor that was several hundred eff...Was on an S5W reactor that was several hundred effective full power hours PAST nominal end of life. That's right we ran PAST the empty gauge! ;-) We definitely had periods of xenon preclusion (shutdown after a flank run). In fact we were worse than what they tell you to worry about near end of life. Since we were PAST end of life.<br /><br />Also the decay heat was very serious. Nothing you couldn't handle. But went to another boat and was a little appalled that they did not take a loss of cooling (in the drydock) seriously. They were probably fine but they had not calculated a grace period. So the "ethic" is to treat it super seriously. Coming from a much older plant, I really had this ethic personally.<br /><br />The other strange thing, not mentioned, is some abnormal behavior in terms of reactivity of the control rods. IOW, you had to shim the rods more to get responses at times. (I don't remember exactly the details, but some ORSE board member was fascinated by it.)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-26580129.post-83348648791882729342019-05-27T18:35:13.615-07:002019-05-27T18:35:13.615-07:00Excellent! Regarding the Fukushima disaster, I tal...Excellent! Regarding the Fukushima disaster, I talked to an American engineer who was on the Fukushima construction project. The design had the electrical switch gear, also called the DC bus, in a waterproof room, as it is in every American nuclear plant at which I have worked. The Japanese government officials in charge refused to allow that. Lose the DC bus, lose the plant.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-26580129.post-83262735095244703342018-10-31T08:07:11.315-07:002018-10-31T08:07:11.315-07:00Great post, I'd forgoton this stuff!
SimonGreat post, I'd forgoton this stuff!<br /><br />SimonSimonhttps://www.blogger.com/profile/12959351344828955925noreply@blogger.com