ML20079H150
| ML20079H150 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 10/03/1991 |
| From: | James Fisicaro ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 0CAN10907, CAN10907, NUDOCS 9110100175 | |
| Download: ML20079H150 (5) | |
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October 3, 1991 OCAN109107 U. S. Nucient I?cgulatory Commission Document Control Desk Mail Station Pl-l37 Washington, DC 20555
SUBJECT:
Arkansas Nuclear Onn - Units 1&2 Docket Nos. 50-313 and 50-368 1.icensn Nos. DPR-51 and NPI'-6 I
Errors or Chnnges in the Emergency Coro Cooling Syntem Evaluntion Annunl Report for 1990 Gentinmen:
10CFR50.46(n)(3)(ii) requirns the licensen to report each change to or error discovered in an acceptabin ovaluntion model or in the applicat ion of such n muini for the emergency cooling system (ECCS) at lenst annually and its estimated nf fect. thosn changns or errors har on the limiting ECCS analysis. The purpose of this submittal is to prov1<ie the informat ion required by 10CFR50.46(n)(3)(if) for Arkatisas Nuclear one, tiri t t.s 1 and 2 (ANO-1 & 2) for 1990.
ANO-1 Since no minor changes or nrrors to t hn llabcock & Wilcox's (B&W) ECCS Evalunt. ion Models havn occurred, nn nnnual report is not required.
However, a brief summary-of the events t.hnt have occurred since the NRC l
1ssund a f avorable Snfety Evaluntlon Report for t.he current revision of I
the B&W ECCS Evaluntion Model in Octobor 1987 is provided in At.tachment 1.
l ANO-2 ANO-2 is licensnd to the 1974-75 versten of the Combustion Engineering (CE) ECCS Evaluation Model.
Several minor changes / errors havn been addressed in CENPD-279, including Supplements 1 and 2 (son Attachments 2.
i 3 and 4) for t hn current CE Evnluation Model, which was approved by the NRC in 1989.
The not ef fect of these changes /nrrors has resulted in n less than 1"P decrease in Pnnk Clad Temperaturn (PCT).
Due to t he minor impact on the c.rrent CE Evaluntlon Model, it was not deemed nocennary to determinn the applicability of these nffects on older versions of thu l-modol; hence, no errors or changes have been identi fied for the Evaluntion I
model usnd for ANO-2.
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ATTACilMENT 1
SUMMARY
OF SICNIFICANT CllANGES OR ERRORS IN Tile B&W EVALUATION HODEL REPORTED TO Tile NRC AND TIIEIR DISPOSITION in compliance with 10CFR50.46(a)(3)(fi) the NRC has previously~ boon notiflod of.the following two-"significant" chenges in the ILW ECCS Evaluation Model.
It should bo.noted that tho first Atom in actually a potential change to the B&W ECCS Evaluation Model that has conservatively not boon implemented at this time.
1.
Notification:
The reevaluation ofJ the REFLOD3 portion of the B&W ECCS Evaluation Model that incorporated a) steam condensation by ECCS-injected-Ifquid in the reactor vossol downcomer nad b) the separation of tho core and the core
- bypass control volumes during post-LOCA coro reflooding.
(Reference 1)
IllsJLosition:
The NRC was briefed on-these issues on May 5, 19Bfs, and a report that provided the results of the evaluation performod by B&W for the B&W Owners Group was forwarded to-the NRC (Reference 2).
The conclusions cbtained from this evaluation were that the currently approved B&W ECCS Evaluation Model still conservatively predicts peak clad temperature responso and that thero.is no sa fety concern regarding the curront REFLOD3 model.
Thorofore as a result of this ovaluation, no model changes woro made to the B&W ECCS Evaluation Modol.
2.
Notification:
LOCA limits for 177 FA lowered loop eperating-plants (Reference 3).
. Disposition:
.The NRC has boon notiflod of a "significant" change in the application of the B&W ECCS Evaluation Model with respect to the replacement of the BAW-2 critical heat flux (CdF) correlstion with the BWC CilF corrolation.
Evaluations of the BWC CilF correlation have boon completed and reported in Reforonces 3 and 4.
Thero oro no casos which indicated that peak cladding temperaturo (PCT) exceeded 2200F. but there are casos which -
showed a PCT increase of greater than 50r o'er previous results.
In compliance with 10CFR50.46, the NRC was not fied of the chango in PCT
.(References 3 and 4).
It should be noted that, although it is not a chango in the ovaluation model, a chango in the inputs to the ovaluation model has recently boca made by replscing the TACO 2 steady stato fuel pin performanco code with TACO 3.
The NRC was notified of the transition from TACO 2 to TACO 3 fuel pin model (Referenco 5), for the B&W ECCS Evaluation Modnl (Ref oronco 6).
The NRC approved t.his transition in Referenco 7.
O e
e AfTACitMENT 2
T REFERENCES
. 1.
Letter to Mr. G. Ilolahan, USNRC, from Mr. P. F. Guill, Chairman B&W Owners Group Analysis Committee, B&W Owners Group (BWOG) ECCS Evaluation Model REFLOD3, llay 13,1988.
2.
. Letter to Mr. R. F. Dudley, USNRC, from Mr. P. F. Guill, Chairman B&W Owners Group Analysis Committee, Transmittal of an Evaluation of Two Models in the REFLOD3 Computer Code, November 14, 1988.
- 5. -
Letter to Dr. T. E. Murley, USNRC, from Mr. J. II. Taylor, B&W, LOCA Limits for 177FA Lowered I.oop Operating Plants, March 19, 1990.
4.
Letter to-Dr. T. E. Murley, USNRC, f rom Mr. J.11. Taylor, B&W, LOCA Limits for 177FA Lowered Loop Operating Plants, August 23, 1990.
5.
Letter to Dr. T. E. Muricy, USNRC, from Mr. J. II. Taylor, Transition to TACO 3 Fuel Pin Model for Fuel Performance Inpat to ECCS Analysis, July 12, 1990.
6.
BAW-10104A, Rev 5,- B&W Topical Report, B&W's ECCS Evaluation Model, Revision 5, November 1988.
- 7.
1;etter f rom Dr. T. E. Murley, USNRC, to Mr. J. II. Taylor, Acceptance for Incorporating TACO 3 in the Evaluating Model for the Emergency Core Cooling System (ECCS), August 2,1990.
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U..S.
NRC x
October"3, 1991 Pege 2 No "significant" changes (changes having a 50 P or greater impact to_the.
peak clad temperature) or'orrors have been identified for the-CE ECCS..
Evaluat ion Model. - Entergy. Operations, in letter dated May'10, 1991 (2CAN059106), Identified a significant change to t.he ECCS analysis input-assumptions for. containment pressure and temperature.- --Ilowever, a 1
subsequent' review of the reporting requ'irements and guidelines indicate
.that this-change was a change to the input assumpt. ions and not_a change or j
error in the evaluation' model. Therefore,. this chango was not -reportable tnder 10CFR50.46.
Should'you have any questions regarding this submittal, please contact me.
'Very-truly yours, sG4br e u$ secs-w, o
ames J. Jisicato Director, hicensing JJF/ RWC/..j f Attachments cc:
-Mr. Robert Martin
~ U. - S. Nuclear-Regu la tory Commission Region IV 611'Ryan Plaza Drive, Suite 1000
' Arlington, TX 76011 NRC Senior Resident Inspector
-Arkansas Nucleat One - ANO-1 & 2 Number.1, Nuclear Plant Road Russellville, AR 72801 Mr. Thomas W. Alexion NRR Project Manager, Region IV/ANO U. S.-Nuclear Regulatory-Commission NRR~ Mall Stop 11-D-23 One White Flint North-11555 Rockville' Pike Rockville, Maryland 20852 Ms. Sheri Peterson NRR Project _ Manager, Region IV/ ANO-2 U. S. Nucicar Regulatory Commi.ssion
-NRR Mail Stop 11-D-23 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852
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