ML20245L251
| ML20245L251 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 04/25/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20245L241 | List: |
| References | |
| NUDOCS 8905050344 | |
| Download: ML20245L251 (3) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION 1
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' SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION
. RELATED TO AMENDMENT NO. 36 TO FACILITY OPERATING LICENSE NO. DPR-80 AND AMENDMENT NO. 35 TO FACILITY OPERATING LICENSE NO. DPR-82 PACIFIC GAS AND ELECTRIC COMPANY
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DIABLO CANYON NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 DOCKET NO. 50-275 AND 50-323
1.0 INTRODUCTION
By letter dated December 24,1986(ReferenceLAR.86-13),PacificGasand Electric Company (PG&E or the licensee) requested amendments to the combined Technical Specifications (TS) appended to facility Operating License Nos. DPR-80 and DPR-82 for the Diablo Canyon Nuclear Power Plant, Unit Nos.1 and 2, respectively. The amendments chan surveillance intervals for certain reactor trip system (RTS)ge the and engineered safety features actuation system (ESFAS) instrumentation.
2.0 DISCUSSION The amendments revise certain analog channel operational test surveillance intervals defined in TS 3/4.1, " Reactor Trip System Instrumentation," and TS 3/4.2, " Engineered Safety Features Actuation System Instrumentation." Specifically, the surveillance test interval in TS Table 4.3-1 for Functional Unit 20, Reactor Trip System Interlocks, Analog Channel Operational Test, is changed from "S/U(1)"
(prior to each reactor startup) to "R" (at least once per 18 months) for each of the six interlocks. Also, the surveillance test interval in Table 4.3-2 for each of three Tavg-Low-Low signals, Analog Channel Operational Test, is changed from "M" (at least once per 31 days) to "Q" (atleastonceper92 days). Finally, the wording of note (5) of Table 4.3-1 is changed to. state that detector plateau curves are to be obtained and evaluated only for the source range neutron flux channels.
The NRC staff has reviewed each part of the licensee's proposed TS change and finds it acceptable, based on the following:
I 8905050344 890425 DR ADPCK 05000275 PDC
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a.
These amendments increase the surveillance interval for each of six RTS interlocks (TS Table 4.3-1 for Functional Unit 20. Reactor Trip (S stem Interlocks, Analog Channel Operational Test) from "S/U 1 " (
18 months) prior to each reactor shrtup) to "R"(at least once per This change was proposed in WCAP-10271, " Evaluation of Surveillance Frequencies and Out-Of-Service Times for the Reactor Protection Instrumentation System," Supplement 1, dated ' July 1983.
The NRC staff has reviewed and approved most of the changes proposed in WCAP-102/1 in letters dated February 21, 1985 and July 24, 1985. Specifically, changing the RTS interlock.
surveillance interval from "M" to "R" was approved by the staft in its letter of July 24, 1985, fromHaroldR.Denton(NRC)to Mr. L. D. Butterfield, Chairman, Westinghouse Owner's Group.
Therefore, this change is acceptable to the NRC staff for Diablo Canyon.
b.
These amendments change the surveillance test interval in Table 4.3-2 for each of three Tavg-Low-Low signals, Analog Channel Operational Test, from "M" (at least once per 31 days) to "Q" (at least once per 92 days). Enclosure 3 to the NRC letter of July 24, 1985 states that relaxation of surveillance requirements may be acceptable for channels which share measurement signals between the RTS and the ESFAS. For these channels, the requirement to perform periodic channel checks provides a measure of assurance that the shared components associated with these measurement signals are operable.
The Diablo Canyon licensee has stated that the ESFAS Tavg-low-low channels are shared with the RTS channels for overtemperature delta-T and overpower delta-T. The licensee has confirmed that the shared channels are measurement channels, and are not bistable /comparators which could fail in a non-tripped state that would only be detectable by performance of analog channel operational tests. These shared channels are periodically confirmed to be operable by channel checks. Also, the licensee has j
instituted a program to evaluate and address instrument drift for RTS channels including the shared channels. The licensee has stated that in this program, instrument drift is treatca as a random variable in setpoint analyses, thereby providing assurance j
that the channel checks reduce the impact of instrument drift.
Since the above features meet the staff criteria given in to the July 24, 1985 letter, the staff concludes that increasing the surveillance interval for the ESFAS Tavg-low-low channels is acceptable for Diablo Canyon.
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These amendments change the wording of note (5) of Table 4.3-1 to state that detector plateau curves are to be obtained and evaluated only for the source range neutron flux channels, which utilize l
proportional counter detectors. The staff finds this acceptable because the intermediate range and power range neutron flux 1
detectors are boron-trifluoride ion chambers. For such devices, the detector curve is linear, and does not " plateau," and the generation of a plateau curve is not appropriate. Consequently, revised note (5) requires that for the intermediate and power range channels, a test shall be performed that shows that the allowed j
variances of detector voltage do not affect detector operation.
Based on the above, the staff finds the proposed amendments authorizing revision of certain analog channel operational test surveillance intervals defined in TS 3/4.1, " Reactor Trip System Instrumentation,"
and TS 3/4.2, " Engineered Safety Features Actuation System Instrumentation," to be acceptable.
3.0 ENVIRONMENTAL CONSID2 RATION 4
These amendments involve changes in the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20. We have determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration and'there has been no public coment on such finding. Accordingly, these amendments meet the eligibility criteria for categorical exclusion setforthin10CFR51.22(c)v). Pursuantto10CFR51.22(b),no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
4.0 CONCLUSION
We have concluded, based on the considerations discussed above that:
(1)thereisreasonableassurancethatthehealthandsafetyofthe public will not be endangered by operation in the proposed manner, and Q ) such activities will be conducted in compliance with the Commission's regulations and (3) the issuance of these amendments will not be inimical to the common defense and security or the health and safety of the public.
Principal Contr,1butor:
Harry Rood Dated: April 25, 1989 4
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