ML20058G445
| ML20058G445 | |
| Person / Time | |
|---|---|
| Issue date: | 11/26/1993 |
| From: | Thadani A Office of Nuclear Reactor Regulation |
| To: | Russell W Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9312090230 | |
| Download: ML20058G445 (3) | |
Text
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t November 26, 1993
.HEMORANDUM FOR:
William T. Russell, Associate Director for Inspection and Technical Assessment FROM:
Ashok C. Thadani, Director Division of Systems Safety and Analysis
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SUBJECT:
WAIVER OF CRGR REVIEW FOR WCAP-10216-P, REV. 1 I
References:
Memorandum from E. L. Jordan to T. E. Murley, "CRGR Consideration of Topical Reports," September 29, 1989.
Enclosed is the safety evaluation report prepared by the Division of Systems Safety and Analysis in which the staff accepts the proposed revision to l
Topical Report WCAP-10216-P for referencing in licensing applications. The staff proposes that the CRGR review be waived in accordance with the suggested revised procedures in the memorandum referenced above.
WCAP-10216-P, Rev. I contains revisions to the F surveillance incorporated in 5
q the Technical Specifications of Westinghouse-designed cores. These revisions are minor in nature and enhance the existing surveillance methodology by j
accounting for F increases between measurements of grtater than 2 percent.
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The CRGR charter states that the CRGR should revies each of the staff's approvals of topical reports. However, the. staff believes that CRGR review is not necessary because the changes made to WCAP-10216-P are minor in nature and do not change the' methodology previously approved in the initial version of this report.
If you agree that a CRGR review is not necessary, please indicate by signing on the line below. Otherwise, the staff will prepare an-appropriate CRGR package.
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Ashok C. Thadani, Director Division of Systems Safety and Analysis
Enclosures:
As stated EDITED BY: R. Sanders
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William T. Russell DATED:
11/9/93 Approved: CRGR review is not necessary.
Contact:
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- i Mr. Nicholas J. Liparulo, Manager l
Nuclear Safety and Regulatory Activities Westinghouse Electric Corporation P.O. Box 355 i
Pittsburgh, PA 15230-0355 l
Dear Mr. Liparulo:
SUBJECT:
ACCEPTANCE FOR REFERENCING 0F REVISED VERSION OF LICENSING TOPICAL l
REPORT WCAP-10216-P, REV. 1, " RELAXATION OF CONSTANT AXIAL OFFSET l
CONTROL-F, SURVEILLANCE TECHNICAL SPECIFICATION" (TAC NO. M88206) l The staff has reviewed the topical report submitted by Westinghouse Electric Corporation by letter of October 29, 1993. The report is acceptable for referencing in license applications to the extent specified and under the limitations stated in the enclosed report and U.S. Nuclear Regulatory i
Commission (NRC) evaluation. The evaluation defines the basis for acceptance of the report.
The staff will not repeat its review of the matters described in the report and found acceptable when the report appears as a reference in license applications, except to assure that the material presented applies to the specific plant involved. NRC acceptance applies only to the matters described in the report.
In accordance with procedures established in NUREG-0390, the i
NRC requests that Westinghouse Electric Corporation publish accepted versions of the report, proprietary and non-proprietary, within 3 months of receipt of this letter. The accepted versions shall incorporate this letter and the i
enclosed evaluation between the title page and the abstract and an -A (designating accepted) following the report identification symbol.
If the NRC's criteria or regulations change so that its conclusion that the i
report is acceptable is invalidated, Westinghouse Electric Corporation and/or the applicant referencing the topical report will be expected to revise and resubmit its respective documentation, or submit justification for the continued applicability of the topical report without revision of the respective documentation.
Sincerely, Ashok C. Thadani, Director Division of Systems Safety and Analysis
Enclosure:
WCAP-10216-P, Rev. 1 Evaluation
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fELOSURE SAFETY EVALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO TOPICAL REPORT WCAP-10216-P. REV. 1
" RELAXATION OF CONSTANT AXIAL OFFSET CONTROL - F. SURVEILLANCE TECH SPEC" WESTINGHOUSE ELECTRIC CORPORATION 1.
INTRODUCTION In a letter of October 29, 1993, from N. J. Liparulo to U.S. Nuclear Regulatory Commission (NRC), Westinghouse Electric Corporation submitted a revision to topical report WCAP-10216-P, " Relaxation of Constant Axial Offset Control - F, Surveillance Technical Specification," for NRC review. The report describes an NRC-approved methodology developed by Westinghouse for performing power distribution control in Westinghouse-type pressurized-water reactors. The proposed revision accounts for F increases greater than 2 percent between measurements to enhance the exi, sting surveillance methodology.
2.
EVALUATION The heat flux hot channel factor, F,(z), is the maximum local heat flux on the surface of a fuel rod at core elevation z, divided by the average fuel rod heat flux.
For those plants using Constant Axial Offset Control (CAOC) or Relaxed Axial Offset Control (RA0C) during normal operation, F,(z) is shown to be within its limits by performing periodic measurements.
Since F,(z) surveillance is only required when power has been increased by 20 percent of rated power from the previous surveillance, or at least every 31 effective full power days (EFPD), the technical specifications (TS) take into account the possibility that F{ie surveillance, the resulting maximum F (z) value must (z) may increase between surveillances. The TS require that when performing t be compared to the maximum F,(z) determined from the previous m,easurement.
If the maximum F,(z) has increased since the previous determination of F,(z), the TS allow two options: either the current F,(z) must be increased by an additional 2.0 percent to account for further increases in F,(z) before the next surveillance, or the surveillance period must be reduced to every seven EFPD.
The F,ld change by no more than 2.0 percent between monthly flux maps.(z) pena 0 percent was based on the Westinghouse assumption that F, wou This assumption was based on calculations for previous (pre-1983) core designs which pre-date the low leakage loading patterns, high amounts of burnable poisons, and 18-month cycles typical of recent cores.
Recently, some Westinghouse-designed cores have experienced increases in the measured F,(z) as high as 5 to 6 percent between monthly flux maps over certain burnup 1
ranges.
Therefore, for those cores which are predicted to have larger increases in F (z) over certain burnup ranges, a larger penalty will be j
provided on a, cycle-specific basis.
The penalties will be calculated using 1
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. NRC-epproved methods.
The larger penalty will be included in the plant Peaking Factor Limit Report (PFLR) or in the Core Operating Limit Report (COLR) as a replacement for the current 2 percent standard value. Alternatively, the additional penalty in excess of 2 percent may be factored into the W(z) function, which is a cycle-dependent function that accounts for power distribution transients encountered during normal operation. The W(z) function is also provided in the PFLR or the COLR. When the F (z) increase penalty is provided on a cycle-specific basis, TS Surveillanc,e 4.2.2.2.e.1 must be modified to reflect inclusion of this parameter in the PFLR or the COLR.
The staff finds either of these methods for incorporating a larger F,(z) penalty acceptable.
3.
CONCLUSION The proposed revisions to the F, Surveillance Technical Specification in those reactors using CA0C or RAOC for power distribution control are acceptable.
These revisions would allow the incorporation of a larger penalty to account for F z) increases greater than 2 percent between measurements.
These penall(ies may be incorporated in either the plant PFLR or COLR, as described above, and will be calculated with NRC-approved methods. The approved version of WCAP-10216-P, Rev. 1 must be included in the Administrative Reporting Requirements Section of the TS for those plants incorporating the penalty factor in the COLR. Also, TS Surveillance 4.2.2.2.e.1 must be modified to reflect inclusion of this parameter in the pFLR or COLR.
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