ML20086Q371
| ML20086Q371 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 07/18/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20086Q370 | List: |
| References | |
| NUDOCS 9507280015 | |
| Download: ML20086Q371 (4) | |
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UNITED STATES y-3 NUCLEAR REGULATORY COMMISSION E
E WASHINGTON. D.C. 20066-0001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 99 AND 63 TO FACILITY OPERATING i
LICENSE NOS. NPF-39 AND NPF-85 PHILADELPHIA ELECTRIC COMPANY LIMERICK GENERATING STATION. UNITS 1 AND 2 DOCKET NOS. 50-352 AND 50-353
1.0 INTRODUCTION
j By letter dated August 22, 1994, as supplemented by letter dated July 3, 1995, the Philadelphia Electric Company (the licensee) submitted a request for changes to the Limerick Generating Station, Units 1 and 2, Technical Specifications (TSs). The requested changes would revise the TS surveillance requirements (SRs) to add an optional scram insertion time test and revise the TS SRs for control rod block and source range monitoring instrumentation.
I 2.0 EVALUATION i
The licensee requested a revision to SR 4.1.3.2, 4.2.3, and bases section B 3/4.1.3 to provide for an optional method of verifying scram insertion times. The current SR require control rods that may have scram insertion times affected by maintenance to be scram tested at greater than 950 psig i
reactor pressure.
The proposed changes by the licensee will allow control rods to be scram tested at zero reactor pressure and then again at greater than 950 psig but prior to achieving 40% rated reactor power. Although this-optional method would require an additional scram test on the affected drives, the licensee requested this change to allow for operational flexibility during maintenance outages.
The licensee provided the following justification for its proposal:
Operability of control rods from zero reactor pressure up to 40% rated l
core thermal power can be assured by the following:
Development of the 2.0 second scram time limit at zero reactor pressure.
l The 2.0 second time limit was established to account for the variability of scram insertion times as a function of reactor pressure.
The 2.0 i
second time limit was developed to require the same level of scram performance for the re-worked control reds relative to a test performed l
during a hydrostatic test at 950 psig reactor pressure.
Scram time testing at zero reactor pressure.
This verifies proper operation of individual control rod system components required for a rod 9507280015 950718 PDR ADOCK 05000352 t
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' i scram, e.g., scram inlet / outlet valves, electrical solenoids on scram l
valves, hydraulic piping, control rod seals, proper hydraulic control unit (HCU) operation, scram discharge volume system, and hydraulic scram accumulator.
Basic design of the control rod drive (CRD) system. UFSAR [ Updated Final Safety Analysis Report) Section 4.6.3.1.1.5 states that if a rod can be moved by hydraulic drive pressure, then i[t] may be expected to scram since a scram condition results in increased pressure below the control rod.
Operation at low reactor power. There are significant thermal limit i
margins at low reactor power, e.g., power levels less than 40% rated.
The licensee also evaluated the proposed changes against its UFSAR transient analy:es.
The licensee found that the limiting accident is.a control rod drop accident and the proposed SR changes are bounded by the UFSAR Section 15.4.9 i
analysis.
The proposed changes are consistent with those delineated in NUREG-1433, Rev.
- 1, " Standard Technical Specifications, General Electric Plants, BWR/4." The i
NRC staff's evaluation of the similar TS is included in the applicable NUREG-(
1433 bases section.
For completeness, relevant portions of the staff's evaluation are summarized in the following paragraphs.
i When work that could affect the scram insertion time is performed on a control rod or CRD System, testing must be done to demonstrate each affected control rod is still within the appropriate limits. Where work has been performed at high reactor pressure, the SR requirements can be satisfied with one test.
l For a control rod affected by work performed while shut down, however, a zero pressure and high-pressure test may be required.
This testing ensures that, i
prior to withdrawing the centrol rod for continued operation, the control rod scram performance is acceptable for operating reactor pressure conditions.
l Alternatively, a control rod scram test during hydrostatic pressure testing could also satisfy the SR.
The frequency of once prior to exceeding 40% power is acceptable because of the capability to test the control rod over a range of operating conditions and the more frequent surveillances on other aspects of control rod OPERABILITY.
Accordingly,'the proposed TS provide assurance that control rod scram time will be verified at operating conditions after control rod maintenance, and I
therefore, are acceptable.
The licensee has proposed TS changes to Sections 4.3.7.6 and 4.9.2 and Table 4.3.6-1 associated with the surveillance requirements of control rod block and source range monitoring instrumentation.
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l The proposed changes include:
A. Elimination of functional tests of rod block monitor, average power range monitor, intermediate range monitor (IRM), source range monitor (SRM), and reactor coolant system recirculation flow prior to plant startup.
B. Change of the frequency of SRM functional test in operating condition two from weekly to monthly.
C. Change of the frequency of IRM and SRM calibration test from semi-annual to refueling.
D. Addition of a note exempting during shutdown the provisions of TS 4.0.4 provided the SRM functional test is performed within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after the IRMs are in range two or below.
E. Addition of a note exempting the provisions of TS 4.0.4 provided the surveillance of the reactor mode switch is performed within one hour after the reactor mode switch has been placed in the shutdown position.
The licensee stated that the proposed changes will be implemented in line with the Improved Standard Technical Specifications and will eliminate unnecessary testing, minimize delays in plant startup, and provide clarity in allowable surveillance test exemption. The licensee also stated that the proposed changes do not alter equipment configuration or operation and there is no reduction in plant safety.
Based on the staff's evaluation, the proposed changes are consistent with the approved ISTS, NUREG-1433 and will reduce the surveillance tests and corresponding shutdown period without adversely effecting the plan safety and are, therefore, acceptable.
3.0 STATE CONSULTATION
- ll In accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments change surveillance requirements. The NRC 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 Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (59 FR 55881). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
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5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, i
that:
(1) there is reasonable assurance that the health and safety of the.
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public will not be endangered by operation in the proposed manner (2)'such J
activities will be conducted in compliance with the Commission's regulations, l
and (3) the issuance of the amendments will not be inimical.to the common defense and security or to the health and safety of the public.
Principal Contributors:
S. Dembek S. Mazumdar t
'l Date:
July 18, 1995 5
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