Japan Earthquake

Japan Earthquake | Page 2018

@dean , like how many hours would it take to reach cold shutdown after a SCRAM.
by Peter Melzer 7/26/2011 2:30:38 AM

Dean, if you have a few minutes tonight or tomorrow I have the Plutonium article ready for peer review. wp.me
by lillymunster 7/26/2011 2:32:36 AM

@ Peter, not a good comparison as the reactor was much smaller in size and wasn't a BWR however, once the reactor scrammed it would typically take 8 hours and approximately 4 hours of that was to cool down the PCS, decay heat removed in less than 1 hour..
by dean 7/26/2011 2:33:19 AM

reactors in the USA have made outage durations shorter and shorter to refuel to maintenance and get back up on the GRID ... more profits.... in order to do that they allow tons of maintenance to be done while the reactor is running by putting some systems into LCO's while the maintenance is going on.. that way the outages can be more dedicated to fuel change and more critical maintenance and modifications.... as opposed to japanese reactors where they don't allow much maintenance to be performed while the reactor is operating and thus have longer outages
by dean 7/26/2011 2:36:16 AM

John M. Mahoney, innovations leader for Entergy Corp., sums it up as "another day, another million dollars." Each day of a power plant outage means purchasing about $1 million in replacement power.
by dean 7/26/2011 2:38:07 AM

@dean Is it considerably more dangerous to do those kinds of maintenance while running?
by lillymunster 7/26/2011 2:38:56 AM

I visited a nuclear power plant in Georgia @ Peter and they were running 12 days behind schedule and they had pumped 21 million dollars into catching things up to get back on schedule... it's a huge money issue
by dean 7/26/2011 2:38:57 AM

@ lilly .. no... a typical plant technical safety requirements document allows taking a system (usually instrumentation is 2:3.. 3 channels with 2/3 logic to scram,,, and reduce it to 1:2 in the LCO "limited condition for operation")..
by dean 7/26/2011 2:40:20 AM

the LCO's have time limits so they must complete maintenance in that time frame or go to an action item which for some systems could mean lower power or shutdown
by dean 7/26/2011 2:41:05 AM

it's done all the time at nuclear power plants in USA.. but I was wondering why outage durations in japan took so long and it's the maintenance issue that drives durations.. not the refueling part
by dean 7/26/2011 2:41:44 AM

@dean , that chimes well with the PTLR doc you posted on Wolf Creek which is a PWR. The fastest rate they allow is 38 degrees C/h. Using that it would take about six hours to reach less than boiling temp. Unfortunately, in the records Elaine posted for Unit 1 last night, the entries for these rates are empty.
by Peter Melzer 7/26/2011 2:42:04 AM

@ Peter I am quite sure they exceeded all cooldown and depressurization rates on fuku after the EQ and tsunami.. .
by dean 7/26/2011 2:44:04 AM

most plant engineering departments have to keep track of the thermal and pressure cycles as design limits can be made on them.. for components
by dean 7/26/2011 2:45:10 AM

@dean , I wondered about that maintenance too. Do people wear respirators when they go into the dry well?
by Peter Melzer 7/26/2011 2:46:29 AM

I was searching for a document on performing maintenance online @ Peter, they pick a system or instrument that has an LCO associated with it and one that is in an accessible area.. I'm sure they would have rad engineering survey etc.. I'm not certain if they routinely perform ones where they have to be in respirators or suited up.. but they probably do
by dean 7/26/2011 2:52:06 AM

as for going into the dry well area.. I wouldn't think they would go in while operating.. as it has the double air lock doors right?
by dean 7/26/2011 2:52:49 AM

@ lilly.. that plutonium write up could use some word smithing i belive
by dean 7/26/2011 2:53:18 AM

@dean , I am asking because the dry well is supposed to be filled with nitrogen when the reactor is working, and I was wondering how you could walk in there.
by Peter Melzer 7/26/2011 2:54:03 AM

@dean sure. :-) If you have wording suggestions or find technical issues that need to be corrected just let me know. I will probably work on cleaning it up a bit tomorrow.
by lillymunster 7/26/2011 2:54:38 AM

www.roadtechs.com job for the risk based maintenance done on-line
by dean 7/26/2011 2:56:33 AM

@ Peter I don't think they go in while operating into that area
by dean 7/26/2011 2:57:10 AM

@ lilly I will get something done up and put on gmail
by dean 7/26/2011 2:57:31 AM

www.nrc.gov example of drywell entry where the workers were exposed to a radiation beam
by dean 7/26/2011 3:01:13 AM

Exelente articlr please rea www.independent.co.uk
by Majj 7/26/2011 3:04:33 AM

Analysis: Sticking with nuclear could be costlier Japan option www.reuters.com
by Panserbjorne9 7/26/2011 3:08:31 AM

@Majj that is an excellent but sad article. :(
by Panserbjorne9 7/26/2011 3:09:07 AM

Fight over radiation dose limits highlights gov't chaos in early days of nuke crisis mdn.mainichi.jp
by Panserbjorne9 7/26/2011 3:10:37 AM

@dean , you mean the incident report? Sure did, very scary.

by Peter Melzer 7/26/2011 3:11:28 AM

that's why I don't think they enter that area during operation but many instrument racks, equipment etc are outside that area and can be taken out of service to perform maintenance
by dean 7/26/2011 3:12:42 AM

Reposting this for any of the later arrivals that may not have seen the video. National government officials meet with Fukushima prefecture (regional) citizens about the radiation and evacuation issue
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by lillymunster 7/26/2011 3:20:11 AM

@lillymunster, those guys need a course in public relations. If they continue to act that tepid, they soon will have a revolt on their hands. I must say that Japanese are very polite. In Germany, the urine samples would have flown toward the podium.
by Peter Melzer 7/26/2011 3:24:04 AM

@Peter Melzer around here I think the good old boys would have started throwing punches.
by lillymunster 7/26/2011 3:26:05 AM

@...actually, the traditional missiles for these occasions are eggs and tomatos. They would have flown at the moment the government guy said "you are free to leave the area."
by Peter Melzer 7/26/2011 3:27:35 AM

@lilly, I wish they would have doused him with the urine!
by Lurking 7/26/2011 3:30:26 AM

@Lurking I think it did more for their cause that they were so civil even though they were all clearly angry and desperate.
by lillymunster 7/26/2011 3:31:11 AM

@Lilly, agreed. I loved it when the guy blocked the elevator buttons! They so badly want to be heard and understood. They want the government to help them.
by Lurking 7/26/2011 3:32:00 AM