ML20062F445
| ML20062F445 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 11/13/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20062F437 | List: |
| References | |
| NUDOCS 9011270272 | |
| Download: ML20062F445 (4) | |
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.g UNITED STATES g
NUCLEAR REGULATORY COMMISSION
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- l WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NOS. 115 AND 97 TO FACILITY OPERATING LICENSE NOS. OPR-70 AND DPR-75 PUBLIC SERVICE ELECTRIC & GAS COMPANY PHILADELPHIA ELECTRIC COMPANY i
DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY SALEM GENERATING STATION, UNIT NOS. 1 AND 2 i
DOCKET NOS. 50-272 AND 50-311 l
1.0 INTRODUCTION
L By letter dated December 24, 1987, and supplemented by letters dated February 26 1990, June 20, 1990, June'28, 1990, and September 19, 1990, PublicServIreElectric&GasCompany(PSE&G)requestedamendmentsto Facility Opr, rating License Nos. DPR-70 and DPR-75 for.the Sales Generating Station, l'ait Nos.1 and 2.
The proposed amendments would revise Salem Unit No. 2' Technical Specification (TS) 3/4.3.4 and the associated bases for To:oine Overspeed Protection surveillance requirements. Salem Unit' No. I currently has no technical specifications addressing turbine overspeed )rotection. This amendment would add these specifications to 1
the Salem Jnit No. 1 TSs.
Additional.information on turbine valve test frequency-was provided in the February 26, 1990 letter. The June 20, 1990 supplemental letter included an additional provision in the event unacceptable flaws or excessive corrosion are=found'upon turbine valve inspection, to require all' other valves of that type to be inspected. The June 28' 1990 and September 19, 1990 supplemental letters forwarded the corrected and retyped TSs pages. for the proposed amendments. The June 20, 1990,
. June 28, 1990, and September 19, 1990 supplements did not increase the scope of the original amendment request and did not affect the staff's N
original no significant hazards determination.
2.0' EVALUATION
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The-proposed amendments would change;the TS' surveillance test frequency for the turbine stop valves, control valvec, hot-reheat stop valves,.and gy w
. hot-reheat intercept valves.
Rather than having a specific turbine valve 18 test frequency in the TSs, the licensee propose:, to use a turbine valve-pc testing frequency-determined'by the methodology presented in Westinghouse Electr.ic Corporation Topical Report WCAP-11525, "Probabilistic Evaluation 5E of the Reduction in the Turbine Valve Test Frequency," that meets the M G-established NRC acceptance criteria for the probability of a missile ejection incident of less than 1.0 X 10-b per However, the turbine valve test interval shall not exceed one year., year.
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- For the Salem Units, the licensee tests four high-pressure turbine stop valves, four high-pressure turbine control valves, six low-pressure hot reheat stop valves, and six low-pressure hot reheat intercept valves. Currently, Sales turbine valve testing is performed on a weekly basis.
In order to conduct turbine valve testing, the reactor power level must be reduced to between 85 percent and 90 percent of full power due to the reduced steam flow to the turbine generator and the limited steam that can bypass the turbine.
Reducing power is typically achieved by boron addition to the reactor coolant system (RCS) with control rods being used primarily'for axial flux distribution (Delta 1) control.
Current operating procedures call for an operator to be stationed at the valves to check for movement during turbine valve testing.
Testing of the turbine valves involves movement of the stem from its position prior to j
testing to the full closed position and returning the valve stem to the y
original position.
The control valves and stop valves test circuits are L
electrically interlocked to prevent the testing of more than one at the same 1-time. Similarly, the test circuits for the reheat stop valves and reheat intercept valves are. interlocked so that it is not possible to test the reheat stop and interceptor valves on one side of the turbine generator unit when the valves on the other side are in other than the. full open position.
'Upon return to full reactor power, the added boron must be removed from the RCS. The boron dilution required to return the reactor.to full power involves a substantial-amount of water which must be processed by Consequently, the reactor power cycling described above (plant systems.1)pl thermal and pressure cycles on plant equipment, (2) increases the probability of equipment failures which may lead to reactor trips, (3) increases the-I amount of liquid and solid radioactive waste.that results-in an increase to plant persor.ael exposure, and (4) places the plant operator in a vulnerable i
position where an inadvertent reactor trip is more likely during'the transient power reduction and increase.
4 In support of this amendment request, the licensee references the Westinghouse Topical Report WCAP-11525. Topical Report WCAP-11525 was prepared by y
Westinghouse Electric Corporation for the Westinghouse Owners Group (Turbine.
l Valve Test Frequency Evaluation Subgroup). WCAP-11525 provides a detailed probabilistic basis for extending the testing interval for turbine valves.
The methodology described in WCAP-11525 for determining turbine valve test a
frequency has received staff approval in a supplemental safety evaluation J
report dated November 2,1989. Prairie Island served as the lead plant for the extended turbine valve surveillance interval issue. Using the.
WCAP-11525 methodology, the llcensee.has calculated the probability of l
total turbine missile generation / ejection for'each of the Salem units 'of L
less than 1.0 X 10-5 per year. The staff has determined that this meets l'
the NRC acceptance criterion of a total turbine missile generation probability of less than 1.0 X 10-5 per year.. Based on the above, the
. staff finds this acceptable.
Jtf t The February 26,lve history and supplementary plant specific information199 Salem turbine va
.- The licensee informed the staff that the Salem Unit 2 turbine valves were tested 119 times during the review period. The review period was from ~ January 1984 through September 1989. Salem Unit 1 turbine valves were tested 103 times during the referred period although Unit 1 turbine valve tests are not sub bct to TS requirements. The licensee also noted that during the turbine V M ye test period, there were no instances of unplanned turbine design overspeed (greater than 120 percent of operating speed). Also, there were no single turbine valve failures that could have led to turbine overspeed condition.
As indicated in the February 26, 1990 supplemental letter, the licensee has committed to maintain, in an audital,la manner, and share all available turbine valve failure information with Westinghouse, the manufacturer, in support of their turbine valve component failure data base. PSE8G will review turbine valve fail ~ rate information at least once every three years and update when more than minor changes occur in the data base. The licensee has also committed to reevaluation of the Turbine Valve Testing Frequency probabilistic analysis (by the WCAF-11525 methodology) when any changes to the turbine system are made in accordance with 10 CFR 50.59 or when a significant upward trend in the valve failure data is identified. The staff finds these commitments acceptable.
The June 20, 1990 supplemental letter provided clarification of the actions to be taken following inspection of turbine valves.
PSE&G has adt.ed a-provision to the original-license amendment request for. additional inspe: tion of valves when unacceptable flaws or excessive corrosion is found when inspecting turbine valves. The additional requirement involves the insp9ction of all valves of;the type that were found to be unsatisfactory. PSF &G has indicated that the definitions of unacceptable flaws and excessive corrosion will be included in the station implementing procedures. The staff has determined that this added requirement is acceptable..
The September 19, 1990 letter provided a corrected and updated page XII of the Salem 1 Table of Contents. These were administrative changes that the-staff finds acceptable.
In conclusion, Salem Unit Nos.1 and 2 were primarily designed for base load
. operation. Load following and load reduction increases the probability of equipment failure, which may lead to reactor trips. Salem operating experience indicates that during _ the turbine valve test period from January 1984 to September 1989, there were no single valve failure that could have led to turbine overspeed conditions. Based on operating experience, test results, and calculated probabilities for turbine missile ejection for Salem Unit Nos.
I and 2, the staff finds the proposed change in turbine valve testing frequency acceptable.
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3.0 ENVIRONMENTAL CONSIDERATION
These amendments involve a change to a requirement with r% pect to the installation or use of a facility component located wMnin the restricted area as defined in 10 CFR Part 20 and changes to tiie 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 Commission has previously issued a proposed finding that-the amendments involve no significant hazards consideration and there has been no ublic comment on such finding. Accordingly, the amendments meet the eli ibility criteria for categorical exclusion set forth in 10 CFR51.22(c)9). Pursuantto10CFR51.22(b),noenvironmentalimpact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
4.0 CONCLUSION
The Comission made a proposed determination that the amendments involve no significant hazards Register (55 FR 12599). consideration which was published in-the Federal on April 4, 1990 and consulted with the State of New Jersey. No public comments were received and the State of New Jersey, did not have any comments.
The staff has concluded, based on the considerations discussed above, that-(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will.be conducted in compliance with the Connission's regulations and the issuance of the amendments will 'not be inimical to the common-defense and security nor to the health and safety of the public.
Dated: November 13, 1990 Principal contributor: M.-Franovich
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