ML20236D971
| ML20236D971 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 03/15/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20236D962 | List: |
| References | |
| NUDOCS 8903230391 | |
| Download: ML20236D971 (3) | |
Text
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[qsCDEQuq,k UNITED STATES p,
NUCLEAR REGULATORY COMMISSION
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j WASHINGTON, D. C. 20655
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-j SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING l
AMENDMENT NOS. 140 AND 142 TO FACILITY OPERATING l
LICENSE NOS. DPR-44 and DPR-56
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PHILADELPHIA ELECTRIC COMPANY PUBLIC SERVICE ELECTRIC AND GAS COMPANY DELMARVA POWER AND LIGHT COMPANY i
ATLANTIC, CITY ELECTRIC COMPANY PEACH BOTTOM ATOMIC POWER STATION, UNIT NOS. 2 AND 3
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DOCKET NOS. 50-277 AND 50-278 4
1.0 INTRODUCTION
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s By letter dated October 21, 1988, Philadelphia Electric Company requested j
an amendment to Facility Operating License Nos. DPR-44 and DPR-56 for l
Peach Bottom Atomic Power Station Unit Hos. 2 and 3.
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September 7, 1988, Philadelphia Electric Company (PECo) y letter dated requested chan 1
to several of Peach Bottom Atomic Power Station Units 2 and 3 (PB 2&3)ges Technical Specification-s (TS). The primary request was to change the requirement for the source range monitor (SRM) minimum count rate for operability during startup from 3 counts per second (cps) to 0.7 cps with a signal-to-noise (S/N) ratio of two or more.
There was also a secondary request for an administrative change to replace a phrase previously inadvertently deleted.
The initial staff examination of the primary request resulted in a phone conversation between members of the staff and PECo.
It was indicated to PECo that, based on a previous discussion between the staff and General Electric (GE), the staff had reservations about the adequacy of the proposed count rate and S/N combination. The staff requested that PEco contact GE and get their insight on the problem and the S/N requirements.
As a result of this interaction on October 21, 1988, PEco submitted a revised request (replacing the initial request in its entirety) providing a specification with a functional relationship between minimum count rate for operability and S/N ratio for an SRM during startup operations. This specification is based on an analysis by GE as discussed in the supplementary information provided with the licensee's letter of November 30, 1988.
This submittal provided additional detailed information and did not change or modify the submittal of October 21, 1988.
8903230391 890315 PDR ADOCK 05000277 P
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2.0 EVALUATION In common with a number of other reactors, Peach Bottom 2 and 3 (PB2&3) i have TS requiring two SRM having count rates of 3 cps or more when withdrawing control rods for startup.
Because of a long shutdown time, PB283 are not likely to achieve this for the forthcoming restart. The licensee has therefore proposed changes to the TS which would permit such startup operations, when necessary, with a count oate les; than 3 cps.
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similar proposal for reload operations, as addressed by the licensee's j
submittal.of December 28, 1988, will be addreised as a separate license i
amendment application.
l The proposed changes are to TS.3/4.3.B.4 and associated Bases. The changes add, via an asterisk marked footnote, a statement that the.3 cps requirements may be reduced for startups if three (vs two fnr the current specification) SRM Channels meet the limits on count rate vs S/N ratio provided in proposed TS Figure 3.3.1.
As an example, a count rate of 0.8 cps is allowed if the S/N ratio is about' 25 or more.
Figure 3.3.1 is based on the new analysis by GE for PB2&3 of SPF downscale nominal trip setpoint vs S/N ratio.
SRM minimum count rates have previously been lowered for several reactors, with GE concurrence, to 0.7. cps with a S/N ratio of 2 for first cycle startup with weak neutron sources resulting from delayed schedules. GE later evaluated this reduction for reload cores (with increased noise) and found that an increased S/N limit is required to achieve the same probability of detecting real signals This analysis was done at PECo's request (as a plant specific analysis) for PB2&3. Thisanalysis(forSRM downscale trip setpoint determination) involves several assumptions about' the signal and noise characteristics and probability requirements, and uses the new standard GE setpoint methodology for setpoint uncertainties.
The assumed signal characteristics are straightforward and acceptable. A primary assumption is that there will be only a 5 percent probability of incorrectly detecting neutrons when they are absent and a 95 percent probability of detecting them when present. This is a reasonable criterion. The NRC review of these various assumptions and probability requirements, and of the analysis methodology concludes that an acceptable analysis has been developed to provide the SRH dowd5cale setpoint and corresponding TS limit for SRM operability.
The lower count rate might result in a slightly lower initial neutron flux level for the control rod drop and withdrawal event analyses.
- hwever, the staff agrees with the licensee's conclusion that the resul of such events are not significantly affected by the change.
The review thus concludes that the proposed change to PB2&3 TS 3/4.B.4 (and Bases), providing an alternate limit for control rod withdrawal during startup when at least three SRM meet the limit of Figure 3.3.1, is acceptable. This approval is specific to the Peach Bottom units.
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1 The licensee has also proposed several administrative changes to correct i
Technical Specification (TS) 4.3.C.1 of the Unit 2 TS to state that scram j
time testing may be accomplished during operational hydrostatic testing or during startup. This would restore a phrase that was inadvertently omitted in an earlier amendment application and would make the Unit 2 TS i
identical to the current Unit 3 TS in this regard. The licensee also proposes to correct the abbreviation for the Rod Block Monitor in TS 3.3.B.5.a.
These changes are straight forward and are acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
S These amendments involve a change to a requirement with respect to the I
installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes to the surveillance requirements.
The staff has 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 Comission 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, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFP, 51.22(b), no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of the amendments.
4.0 CONCLUSION
The Comission made a proposed determination that the amendrents involve no significant hazards consideration which was published in the Federal Register (53 FR 53096) on December 30, 1988 and consulted with the State l
of Pennsylvania.
No public coments were received and the State of Pennsylvania did not have any coments.
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that tha health and safety of the public will not be endangered by operation in the proposed manner, and l
(2) such activities will be conducted in compliance with the Comission's regulations, and the issuance of the amendments will not be inimical to l
the comon defense and security or to the health and safety of the public.
Principal Contributor:
H. Richings Dated:
March 15, 1989 l
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