ML20078G788
| ML20078G788 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 01/26/1995 |
| From: | Kofron K COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| BW-95-0011, BW-95-11, NUDOCS 9502030256 | |
| Download: ML20078G788 (4) | |
Text
,.
1 1 Commonwrith Edison
- Brtidwood Nuclzir Powsr St1 tion n
T flouta #1, Box 84
- d.. Braceville, Illinois 60407 -
Telephone 815/458-2801 January 26, 1995 BW/95-00ll Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 Attention:
Document Control Desk
Subject:
Report Of the Findings Regarding Failure Of A Review Criterion During t.n. 2 Braidwood Unit 2 Cycle 5 Rod Swap Testing
References:
3 1.
Letter, C.O. Thomas (NRC) to E.P. Rahe (Westinghouse), " Acceptance for Referencing of Licensing Topical Report WCAP-9863(P), WCAP-9864(NP) ' Rod Bank Worth Measurements Utilizing Bank Exchange,'" dated May 1983, with Enclosure.
2.
- Letter, E. H. Young to D.J. Miller,
" Evaluation of Rod Swap Results for Braidwood Unit 2 Cycle 5," BR2CS/046, dated January 9, 1995.
Gentlemen:
Section 2 of the Enclosure to Reference (1) requires that a report of the findings of the investigation of failure to meet a review criterion during Rod Swap testing be provided to the Nuclear Regulatory Commission within 75 days of the test.
t Measurements conducted and analyzed on November 16 and 17,
~1994, in accordance with WCAP-9863-A, " Rod Bank' Worth Measureme s Utilizing Bank Exchange," failed the review criterion for Control Bank B of the Rod Control System.
The review criterion for Control Bank B is that the difference between measured and predicted reactivity worth must be less than or equal to i 15%.
Measurements conducted during the Rod Swap testing indicated that the difference between measured and predicted reactivity worth for Control Bank B was -16.7 %.
Comed, Nuclear Fuel Services, has conducted an investigation into the failure of the review criterion, as reported in l
Reference 2 (attached).
This investigation included verification that neutronic design computer models were generated in accordance with current approved methodology, and 9502030256 950126
/ g0 PDR ADOCK 05000456 r
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that the predictive calculations performed to generate the predicted values for Rod Swap testing were correct.
No errors were found that would have caused failure of the review criterion.
Since no errors in the predicted values were found that could have caused the failure, an evaluation of the effect of the failure of the review criterion was conducted.
This evaluation determined that the failure had negligible impact on safety analysis parameters.
Current neutronic design methodology does not include explicit corrections to match predictions to measured values.
All other measurements obtained during performance of Low Power Physics testing for Braidwood Unit 2 Cycle 5 showed close agreement to predictions.
As a result of this agreement and the above-mentioned investigation, no corrective actions for the failed review criterion are deemed to be appropriate.
Please direct any questions regarding this submittal to Douglas S. Huston, Braidwood Regulatory Assurance, Licensing Group, (815)458-2801 extension 3182.
Sincerely, 1
.l ?
v' K. L. hof n
Station Manager Braidwood Nuclear Station KLK/DRL/dla o:\\corresp\\zcsteno Attachment cc:
S.
G.
DuPont, Senior Resident Inspector, Braidwood R.
R. Assa, Braidwood Project Manager, NRR B.
Clayton, Branch Chief, RIII T. A. Rieck, Nuclear Puel Services D. M. Saccomando, NLA K. G. Bartes, Regulatory Assurance Supervisor L. Kepley, System Engineering
January 9,1995 BR2C5/046 y
4 Mr. David J. Miller Technical Services Superintendent Braidwood Station
Subject:
iEvaluation of Rod Swap Results for Braidwood Unit 2 Cycle 5
References:
1)
" Revised Westinghouse Physics Test Results Evaluation Criteria",
Westinghouse letter 94CB*-G-0063/94CW*-G-0049, dated April 25, 1994.
2)
" Acceptance for Referencing of Licensing Topical Report WCAP-9863(P), WCAP-9864(NP)' Rod Bank Worth Measurements Utilizing Bank Exchange"', C. O. Thomas (NRC) to E. P. Rahe, Jr.
(Westinghouse).
3)
"Braidwood Nuclear Plant Unit 2 Cycle 5 Reload Safety Evaluation",
by S. L. Davidson, et al., dated October 1994.
4)
"Braidwood Unit 2 Cycle 5 Revised Reload SPIL Transmittal",
Westinghouse letter 94CB*-G-0174, dated October 11,1994.
5)
" Rod Swap Misprediction Review", by D. J. Wise, BR2C5 NDN, NR-30, dated December 8,1994.
6)
"Braidwood 2, Cycle 5 Rod Exchange Data", R. C. Lee to D. J.
Miller, BR2C5/039, dated November 1,1994.
The Rod Swap results for Control Bank 8 from the Braidwood Unit 2 Cycle 5 startup physics testing violated the review criterion specified in References 1 and 2.
The review criterion for the difference in predicted and measured reactivity worth for Control Bank B is (+/-)15%. The results from the Rod Swap test showed a difference in the measured to predicted Control Bank B worth of (-)16.7%.
The Reference 2 document requires that when there is a violation of a review criterion that an investigation be performed and solutions determined within 60 days, and a report supplied to the NRC within 75 days. To support this regulatory requirement, Nuclear Fuel Services (NFS) has performed a review of the Rod Swap information supplied in Reference 6. This review consisted of verifying that the' neutronic design models used were generated properly, and calculations performed for the Reference 5 Rod Swap transmittal are correct.
The review of the models and calculations, performed in Reference 5, found no errors that would cause the failure of the review cnterion for Control Bank B. Since no
se Janu ry 9,1995 BR2C5/046 errors were found in the predicted values supplied by NFS in Fseference 6, an evaluation of the Braidwood Unit 2 Cycle 5 Safety Parameter Interaction List (SPIL),
Reference 4, and the Reload Safety Evaluation (RSE), Reference 3 was performed to determine the impact caused by the misprediction. The evaluation determined that there is negligible impact on the analyses and the Reference 3 RSE and Reference 4 SPil are still valid. Also, the operational data transmitted to Braidwood for use in Braidwood Unit 2 Cycle 5 is sti I valid for use and does not need to be revised.
Considering the conclusion from the SPIL/RSE evaluation discussed above, no corrective actions are required.
Should you have any questions or comments to this memo, please contact Douglas J. Wise at G. O. Ext. 8129.
i Everett H. You y~
PWR Nuclear Design Supervisor Nt. clear Fuel Services j
EHY:DJW:pc cc:
L. K. Kepley NFS-CF
' D?R: Laws'on D. R. Redden /W. J. Funke l
l
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