Japan Earthquake

Japan Earthquake | Page 2228

Looking at some radionuclide contamination studies of foliage, I'm not sure that the groove in pine needles is the reason. Some pine needles don't have grooves. But they do have stomates (pores). Also, pine needles don't drop for years, so accumulation would be higher on them. The original studies look like they were done in Japan, actually 1980s. And most common pine tree in Japan. There are seasonal variations of contamination, you see. Not to mention fallout patterns and types of radionuclides. Pine needle wax may hold radionuclides longer too. Someone should research this.
by Cryptococcus 8/24/2011 7:09:11 PM

@lillymunster Doesn't that just say the alarm should go off at 0.01g?
by es 8/24/2011 7:09:56 PM

@RadioGuy could you clerify... 5.9-6.1 is that the design factor or the "trip" setting for the seismic shutdown? not sure what way you mean? I took the measurement to mean design factor... maybe I miss read. thanks
by FITTER 8/24/2011 7:11:10 PM

@Cryptococcus I was looking for a good photo, but an image search brings up a lot. Many species have a groove down the center of the needle (like an open book spine) which lets capillary action drtaw water down to the base, and many needles are clustered at the bases of the needles, though that varies by species. Hemlock, for instance, has very pronounced grooves.
by RadioGuy 8/24/2011 7:11:20 PM

@FITTER They said in a quick response to the 12 plants "unusual events" that the reactors were safe up to 59.-6.1, so that would be the design basis, I guess.
by RadioGuy 8/24/2011 7:12:37 PM

back.. I have so much to catch up on
by dean 8/24/2011 7:12:41 PM

The Nuclear Regulatory Commission (NRC) requires all of its licensees to take seismic activity into account when designing and maintaining its nuclear power plants. When new seismic hazard information becomes available, the NRC evaluates the new data and models and determines if any changes are needed at plants. The newest seismic data suggests that although the potential seismic hazard at some nuclear power plants in central and eastern states may have increased beyond previous estimates, all operating nuclear plants remain safe with no need for immediate action. I WOULD SAY NRC may be eating their words
by dean 8/24/2011 7:14:22 PM

The book "Wormwood Forest: A Natural History of Chernobyl" has lots of good info on pine trees and radioactive fallout. One of the reasons why they studied the pine there was because it was the most common tree around the Cherynobyl site.
by Cryptococcus 8/24/2011 7:15:07 PM

www.canadianchristmastrees.ca

This too leads to concentration. Look at the basal clustering.
by RadioGuy via Canadianchristmastrees.ca 8/24/2011 7:15:54 PM

@RadioGuy good point!
by Cryptococcus 8/24/2011 7:16:26 PM

no pun intended lol
by Cryptococcus 8/24/2011 7:16:42 PM

hello to all
by dean 8/24/2011 7:19:24 PM

Hi Dean!
by lillymunster 8/24/2011 7:24:53 PM

Has the NRC said anything about a review of seismic standards on the east coast? N. Anna has a design basis of 5.9 and someone told me Indian point's is 6.0 That leaves very little margin.
by lillymunster 8/24/2011 7:26:07 PM

@RadioGuy thanks for the info... I thought you were refering to the design factors... The one thought I would have is " set point to alarm and actions to scram" could have different meanings... you could want something to alarm at a lower point than you might for a auto shutdown... see that dean is on board will ask him the safety factor of auto vs manual?
by FITTER 8/24/2011 7:26:09 PM

@dean Hello! hope you are good! Question... Is there a difference in "safety" between a reator being shutdown manually vs an auto shutdown? I could think of a lot of systems we work on that are better brought down manually and in a more controled manner if there are no other "conditions/alarms" requiring that the system come down ASAP?
by FITTER 8/24/2011 7:26:10 PM

@ lilly .. at this rate with all the EQ's and disasters we better syndicate simplyinfo
by dean 8/24/2011 7:26:26 PM

The NRC notification reports for all those Unusual Events yesterday - Current Event Notification Report for August 24, 2011: www.nrc.gov
by es 8/24/2011 7:27:16 PM

@ fitter, a scram is designed to shutdown the reactor to a subcritical state as quickly as possible but from a neutronics stand point. A scram to the plant as opposed to an orderly shutdown places the plant in a transient state that requires a different set of procedures to bring the system to stable state. We have seen that closing off the main steam isolation valves induces a transient on the system for instance
by dean 8/24/2011 7:29:39 PM

it would really be educational for all of us to get some documents to show what happens in a typical reactor control room when a scram is received and... in the event of the reactor recently at N. Anna which did not have the seismic system capable to scram the reactor at the event, but rather from loss of off site power,,, it's very complicated on the transient that Anna went through...
by dean 8/24/2011 7:32:03 PM

@dean
by Majj 8/24/2011 7:34:13 PM

at Anna, full seismic impact was experienced by all the plant from the time of feeling affects from the earth quake on the plant components until the scram came through from the off site power... this, in my opinion, is in the realm of near miss from a melt... and NRC should be called back in to the congressional hearing and GRILLED to the table for why it happened .. "after" they said all reactors are ok in the USA.. .after fuku
by dean 8/24/2011 7:34:27 PM

by Majj 8/24/2011 7:35:38 PM

good one Majj... now.. imagine at least 3 times that number of alarms when you add loss of off site power,,
by dean 8/24/2011 7:36:55 PM

@dean scary very scary
by Majj 8/24/2011 7:37:44 PM

unless you have been through something like that ,, it's just crazy in the control room.. trying to sort out what happened, determine what's safe and what's not, which procedures to be used and which procedures hand off to other procedures to recover the plant.. very complex
by dean 8/24/2011 7:39:18 PM

From Peach Bottom:
PBAPS [Peach Bottom Atomic Power Station] Units 2 and 3 experienced a seismic event which was felt in the control room in conjunction with a seismic trigger alarm set a 0.01G acceleration. The operating basis earthquake alarm of 0.05G was not received.
by RadioGuy 8/24/2011 7:39:54 PM

@dean the emergency generators at N. Anna were inspected twice since late 2010. They had a refueling inspection in late 2010 and another as part of the post Fuku inspection. It had a coolant loss that made it fail. I would think this would have been caught at either the operational test in 2010 or the visual inspection in April.
by lillymunster 8/24/2011 7:39:55 PM

@RadioGuy Operating basis for N. Anna, why did it not trip then? :The Operating Basis Earthquake for North Anna is 0.06 g (5.4 on
the Richter Scale)
by lillymunster 8/24/2011 7:40:49 PM

@lillymunster So are we to assume that Anna didn't have it, or that it malfunctioned?
by RadioGuy 8/24/2011 7:41:05 PM

hopefully @ lilly,, I was reading that one of the 4 diesel Gens didn't start or shutdown after it started..
by dean 8/24/2011 7:43:11 PM

Anna is a PWR plan so we'd have to be up on the safety requirements for that PWR as opposed to the things we've learned on the BWR's...
by dean 8/24/2011 7:43:52 PM

@lillymunster i'm still not convinced that the backup generator that wasn't working during the april inspection isn't the same one that "stopped working" during this EQ. I just would not be surprised if they never fixed it to begin with.
by Panserbjorne9 8/24/2011 7:44:53 PM

@RadioGuy either or.
by lillymunster 8/24/2011 7:45:34 PM

Anyone speak German? Translation of this video reads "Secretly made recordings - Tepco withholds information" : www.youtube.com
by Ian 8/24/2011 7:46:58 PM

@dean one of the emergency generators started then failed due to coolant loss.

@PB the one in the inspection was a portable generator that was sent off to be repaired. They said they have a replacement rented and onsite so I am assuming they meant one of the semi truck trailer type generators. They did a visual inspection of the installed emergency generators at that inspection and missed whatever caused the coolant leak.
by lillymunster 8/24/2011 7:47:31 PM

@Dean do you have any idea if the US now requires 2 emergency generators per reactor or did n. Anna happen to have them because they are newer reactors?
by lillymunster 8/24/2011 7:48:55 PM

[...] According to the Virginia Department of Mines, Minerals and Energy (DMME), the Virginia Tech Seismological Observatory (VTSO) removed all seismographs from around the plant in the 1990s due to budget cuts. [...] enenews.com
by Majj 8/24/2011 7:52:32 PM

when transients occur at these plant especially ones that involve major load shifts on high voltage systems, the transients felt on the system can cause problems, especially when the 4 diesels are trying to come up and get synched on line... who knows maybe they sync'd them wrong that caused the one to go off...
by dean 8/24/2011 7:54:51 PM

@ lilly.. I'm not sure about the 2 diesels per plant now, it's probably been an evolving requirement over the recent years
by dean 8/24/2011 7:55:30 PM

Excessive Radiation Found in Sea Organisms Near Japan's Nuke Plant : According to the statement, the levels of strontium-90, a radioactive isotope of strontium, found in squids are 29 times higher than the average background level of samples taken from China’s coastal waters. [...]
The samples were also found to contain argentum-110m and cesium-134, which are normally difficult to detect in biological samples from China’s coastal waters, the statement said. [...] english.cri.cn
by Majj 8/24/2011 7:57:10 PM

twitter.com!/domvapower
dominion power's twitter info
by dean 8/24/2011 7:58:06 PM

@dean could the sync caused coolant loss or something to act wrong and fail the coolant system?
by lillymunster 8/24/2011 7:59:21 PM

After the plant's four emergency diesel generators started, plant operators discovered that one of the engines had a coolant leak and shut that generator down, the company said.

The operators then started the plant's fifth generator, which is used as a spare. The plant is required to have only three generators available for emergency power, the company said.
by dean 8/24/2011 8:01:49 PM

@ lilly.. I think the coolant leak as this report says could probably have taken the cooling flow or pressure down sufficiently to cause the interlock to go off and shut the diesel down to prevent over heating
by dean 8/24/2011 8:02:47 PM