ML20196D780
| ML20196D780 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 09/21/1998 |
| From: | Collins S NRC (Affiliation Not Assigned) |
| To: | Burrows F NRC (Affiliation Not Assigned) |
| References | |
| NUDOCS 9812020324 | |
| Download: ML20196D780 (2) | |
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q UNITED STATES k
j Ij NUCLEAR REGULATORY COMMISSION e
WASHINGTON. D.C. 205fM001 September 21, 1998 l
MEMORANDUM TO:
Frederick H. Burrows Electrical Engineering Branch D; vision of Engineering FROM:
a irector Office of Nuclear Reactor Regulation
SUBJECT:
RESOLUTION OF FOLLOW-UP ACTIONS OF NRR DPV REVIEW PANEL ON DYNAMIC TESTING OF INSTRUMENTATION CHANNELS AT BRAIDWOOD
Reference:
Memorandum from Brian W. Sheron, Acting Associate Director for Technical Review, to Bruce A. Boger, Director, Division of Reactor Controls and Human Factors, dated January 2,1997, " Follow-up Actions to NRR DFV Review Panel on Dynamic Testing of instrumentation Channels at Braidwood."
l The staff-has completed its review of the follow-up actions identified in the reference memorandum for your differing professional view (DPV) on dynamic testing of instrumentation channels at Braidwood. Based on the information available to you at the time of your initial review and subsequent discussions of your concerns, the staff finds that your concerns regarding the MESAC system dynamic testing methodology appeared to be valid. It was not until additional licensee documentation was reviewed (i.e., plant scaling and error analyses that define test procedures, licensee sensitivity analyses for Byron /Braidwood Updated Final Safety Analysis Report (UFSAR) Chapter 15 events, and testing documentation) that the staff was able to evaluate differences between the testing procedures at Braidwood and other plants. As a result of this evaluation, the staff concludes that the testing methodology at Braidwood is equivalent to the testing done at other Westinghouse plants and meets the plant technical specification (TS) requirements, f
With regard to the acceptable uncertainty for setting dynamic component time constants, an extensive review of industry experience has shown that setting time constant values
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10% more conservative than required by the TS and used in the UFSAR Chapter 15 h/
analyses does not reduce the margin to safety limits and has not caused spurious safety system actuations. Further, the staff concurs with your conclusion that setting time constant values less conservative than used in the UFSAR Chapter 15 analyses and specified in the TS could result in reduction in the margins to safety limits. However, TS requirements restrict the licensee from setting time constant values less conservative than UFSAR Chapter 15 analyses will permit; and, sensitivity analyses have shown that adequate margin exists to account for time constant setting tolerances and that safety limits are not exceeded. NRC guidance to the licensees concerning appropriate consideration of time constant settings is provided in NUREG-1431, Rev 1, " Standard Technical Specifications, Westinghouse Plants," which specifies the appropriate inequality relationships for time constants. The staff, therefore, concludes that additional guidance on setting time constant values is,"not required at this time.
9812O20324 900921 PDR ADOCK 05000456 P
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8 Frederick H. Burrows Details of the above conclusions are provided in the attached memorandum from R. Lee Spessard to Brian W. Sheron.
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l appreciate your willingness to bring your concerns to the attention of the agency via the DPV approach. Please feel free to contact me if you have any further questions.
Attachment:
As stated DISTRIBUTION:
HICB/RF F. Miraglia, (0-5E7)
S. Peterson, (0-5E7)
P. Foust, (0-5E13)
SEE PREVIOUS CONCURRENCE
- DOCUMENT NAME: DPVMEMO.FHB (98-99)
T* receive a copy of this document, indicate in the box: "C' = Cooy without attachment! enclosure
'E' = Copy with attachment / enclosure No copy I
OFFICE HICB:DRCH BC:HICB D:DRCH f
AADT C I 'W E
D h
NAME MWaterman JWermiel RLSpessard BSheron t
DATE 9/15/98*
09/15/98*
O/15/98*
9/17/98*
E09//)/98.
OFFICIAL RECORD COPY l
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