ML110620527
| ML110620527 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 12/21/2010 |
| From: | Office of Nuclear Reactor Regulation |
| To: | Division of License Renewal |
| References | |
| Download: ML110620527 (4) | |
Text
1 DiabloCanyonNPEm Resource From:
Poehler, Jeffrey Sent:
Tuesday, December 21, 2010 10:00 AM To:
Cullingford, Michael
Subject:
FW: Information request - Diablo Canyon - Neutron noise JeffreyC.Poehler Sr.MaterialsEngineer NRR/DCI/CVIB (301)4158353 From: Parks, Benjamin Sent: Monday, December 20, 2010 12:16 PM To: McLellan, Thomas; Poehler, Jeffrey Cc: Wang, Alan
Subject:
RE: Information request - Diablo Canyon - Neutron noise
Im afraid I have little to add.
A number of different effects could be causing neutron noise. In the Diablo case, looks like it was vibration.
In other cases, Westinghouse plants have been known to undergo an upper plenum anomaly where temperatures fluctuate, causing power oscillations and mild xenon transients. In BWRs, some plants undergo bistable flow oscillations in the header cross region of the jet pumps, which propagates into power oscillations picked up by the LPRMs. These noises have a pretty long period, though on the order of minutes.
Perhaps the RIV/DRP folks could shed some light on the regulatory interaction described in the NEI article, but in the other two noise examples I identified, there was no regulatory interaction that I am aware of. One of the bistable flow plants, I know, had to reduce its thermal power level to avoid the oscillations resulting in an overpower condition in excess of their operating license. The upper plenum anomaly plants work their issues out in control space its a bigger problem with 14 cores.
From: McLellan, Thomas Sent: Monday, December 20, 2010 9:50 AM To: Poehler, Jeffrey Cc: Parks, Benjamin; Wang, Alan
Subject:
RE: Information request - Diablo Canyon - Neutron noise
Try Benjamin Parks of the Reactor Systems Branch we work with him a lot on various relief requests. From the attached article sounds like a turbulent flow issue. Tom From: Poehler, Jeffrey Sent: Monday, December 20, 2010 8:04 AM To: Cheruvenki, Ganesh; McLellan, Thomas; Fairbanks, Carolyn; Sheng, Simon; Andruszkiewicz, Edward; Widrevitz, Dan; Sydnor, Christopher; Purtscher, Patrick; Kerr, Matthew Cc: Mitchell, Matthew
Subject:
FW: Information request - Diablo Canyon - Neutron noise
Have any of you ever reviewed anything related to neutron noise monitoring? Im thinking this is something Reactor Systems Branch in DSS or I&C Branch in DE would be responsible for, but I thought I would check with you all first.
2
- Thanks, JeffreyC.Poehler Sr.MaterialsEngineer NRR/DCI/CVIB (301)4158353 From: Wang, Alan Sent: Friday, December 17, 2010 3:53 PM To: Poehler, Jeffrey
Subject:
FW: Information request - Diablo Canyon - Neutron noise
Jeff, I got the Matt is away message. Could you help me with this. Thanks alan From: Wang, Alan Sent: Friday, December 17, 2010 3:51 PM To: Mitchell, Matthew
Subject:
FW: Information request - Diablo Canyon - Neutron noise
Matt, Mike Cullingford had this request from someone from the Spanish NRC?. They saw the Diablo article and was wondering if it might have implications for them. I am not sure what issue with the Trillo plant is but when I read the link it appears to me that the neutron noise was instrumentation we placed inside the reactor to look for vibration and loose parts. Do you know if we have any information regarding this type of instrumentation to determine vibration or loose parts? It is not clear to me what neutron noise they are detecting unless they too are using a similar technology for loose parts. If you have any insights on this I would appreciate it. Alan From: Cullingford, Michael Sent: Friday, December 17, 2010 9:49 AM To: Wang, Alan
Subject:
FW: Information request - Diablo Canyon - Neutron noise
Hi Alan: Could you please guide me as to who is the appropriate person (if not yourself) for me to get the answer to this question? Thank you, mike From: FRANCO MATILLA, Fernando [1]
Sent: Friday, December 17, 2010 4:48 AM To: Fehst, Geraldine
Subject:
Information request - Diablo Canyon - Neutron noise
DearGerri,
OnbehalfofoneCSNCommissioner,weareinterestedinobtainingsometechnicalinformationfromtheNRC.Asyou mayknow,wehavebeenexperiencingabnormalneutronnoiseinTrilloNPP.Theanalysiscarriedoutbythelicensee andtheCSNisunderprogress,withthecooperationofourGermancolleagues(TrilloisGermandesign),whoare carryingoutsimilaranalysis.Inrelationtothis,thefollowingnewshasdrawnourattention:
http://www.neimagazine.com/story.asp?storyCode=2056532
WewouldbeinterestedinobtainingsomeinformationabouttheroleoftheUSNRCincaseithasbeeninvolvedinthe assessmentofthisissue.Sofar,oursearchattheUSNRCwebsitehasbeenunsuccessful.Woulditbepossibletoget additionalinformationregardingtheevaluationofthissituationbytheNRC?Thankyouverymuchforyourcooperation,
FernandoFranco
3
Hearing Identifier:
DiabloCanyon_LicenseRenewal_NonPublic Email Number:
2638 Mail Envelope Properties (Jeffrey.Poehler@nrc.gov20101221100000)
Subject:
FW: Information request - Diablo Canyon - Neutron noise Sent Date:
12/21/2010 10:00:23 AM Received Date:
12/21/2010 10:00:00 AM From:
Poehler, Jeffrey Created By:
Jeffrey.Poehler@nrc.gov Recipients:
"Cullingford, Michael" <Michael.Cullingford@nrc.gov>
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