ML19309F104
| ML19309F104 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 04/23/1980 |
| From: | Utley E CAROLINA POWER & LIGHT CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| NO-80-604, NUDOCS 8004280497 | |
| Download: ML19309F104 (2) | |
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1 April 23, 1980 FILE: NG-3514(B)
SERIAL NO: NO-80-604 Office of Nuclear Reactor Regulation ATTENTION:
Mr. T. A. Ippolito, Chief Operating Reactors Branch No. 3 United States Nuclear Regulatory Commission Washington, D. C.
20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET No. 50-324 LICENSE NO. DPR-62 CORRECTIVE ACTION FOR RELOAD MCPR ERROR
Dear Mr. Ippolito:
Your December 10, 1979 letter enclosed Amendment No. 49 to License No.
DPR-62 for the Brunswick Steam Electric Plant (BSEP) Unit No. 2 which corrected the Minimum Critical Power Ratio (MCPR) limits for the latter part of Cycle 3 as requested in our October 10, 1979 letter. Your letter noted that Carolina Power & Light Company (CP&L) agreed to provide a summary of corrective action taken to avoid recurrence of similar errors in future reloads. A summary of the error and the corrective actions is provided below.
General Electric's (GE) preparation of their Nuclear Dynamics Parameters Data Book for BSEP-2, Reload 2 involved analysis at three (3) exposure points:
BOC-3 (Beginning of Cycle 3); EOC-3 (End of Cycle 3) minus 2,000 MWD /t; and EOC-3.
During the preparation of data files for the generation of their Nuclear Dynamics Parameters Data Book, GE assigns index numbers to the scram, void, and Doppler data which correlates an exposure value with the corresponding reactivity data. The Data Bcok is then prepared automatically by computer from these data files. For this Data Book, the scram and Dopplcr data were assigned one set of indexing numbers, while the void data were assigned the reverse set.
In this instance, different GE engineers developed the Nuclear Dynamics data and assigned inconsistent indexing numbers. As a result, the transients were calculated using inconsistent nuclear dynamics parameters input data and, consequently, the E0C-3 MCPR limit was reported in the Reload Licensing Submittal to be 0.02 lower than the correct value.
GE's design verification procedures normally would have uncovered the use of the BOC-3 void coefficient as part of the EOC-3 data. However, the extended operation of Cycle 2 provided a core condition where the point-model void coefficient and void fractions at BOC-3 and EOC-3 were quite similar. Thus, the void coefficient data reported did not seem obviously incorrect to the GE design verifier of the Nuclear Dynamics Parameters Data Book.
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c e To preclude a similar error in the future, General Electric has implemented two courses of corrective action which are described below:
1.
Associated with each Data Book is a " Data Book Timeshare Instruction File." This file is accessed by the GE engineer prior to preparation of the Data Book.
The file has been up-dated to include instructions to the engineers to verify the correct sequencing of data versus exposure.
2.
The verification guide for the Nuclear Dynamics Parameters Data Book has been changed. A check has been added which requires the GE design reviewer to verify that all data files are consistently sequenced.
These two corrective actions were reviewed by CP&L during our November 7-9, 1979 design control audit of GE at their San Jose, CA. office.
If you have any questions regarding this information, please contact my staff.
Yours very truly, 2W)~/4 5
E. E. Utley f
Executive Vice President Power Supply & Customer Services JAM /t1 4