ML20214J568

Safety Evaluation Supporting Amends 20 & 10 to Licenses NPF-35 & NPF-52,respectively

ML20214J568
Person / Time
Site:	Catawba
Issue date:	11/20/1986
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20214J563	List: ML20214J562 ML20214J568
References
NUDOCS 8612010353
Download: ML20214J568 (4)

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UNITED STATES g

NUCLEAR REGULATORY COMMISSION 3

'j WASHING TON, D. C. 20555 o,,

.,,.<**g SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULAT RELATED TO AMENDMENT N0. 20 TO FACILITY OPERATING LICENSE N AND AMENDMENT NO. 10 TO FACILITY OPERATING LICENSE NPF-52 DUKE POWER COMPANY DOCKET NOS. 50-413 AND 50-414 CATAWBA NUCLEAR STATION, UNITS 1 AND 2 1.

INTRODUCTION By letter dated October 27, 1986, Duke Power Company, et al., (the licensee) submitted a license amendment request to change the technical specificaticn (TS) for the Catawba Nuclear Station, Units I and 2.

The change proposes to increase the speed of the Auxiliary Feedwater (CA) pump turbine specified in TS 4.7.1.2.la.2) from 3600 rpm to up to and including 3800 rpm.

Vith this increase, the CA turbine-driven pump will have added margin to better meet the TS required head and flow.

Subsequently, in a letter dated November 13, 1986, the licensee requested that the proposed amendment contained in the October 27, 1986 letter be granted on an emergency basis. During a surveillance test for Unit 2, which was performed on November 12, 1986 in accordance with TS 4.7.1.2.la.2), the CA turbine-driven pump did not meet the test acceptance criteria.

Unless this pump is returned to operable status by 0305 hours0.00353 days <br />0.0847 hours <br />5.042989e-4 weeks <br />1.160525e-4 months <br /> on November 14, 1986, the unit would have to be cooled down to Pode 4 from Mode 3.

Similar tests for Unit 1, perfomed on November 13, 1986, also did not meet the acceptance criteria. The licensee states that the requested change would allow an increase in the developed head sufficient to meet the TS requirements. The requested change would also provide an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for both units, on a one-time basis, to remain in Mode 3 in order to repeat the test and obtain appropriate measurements for operation at the new rpm value.

II. EVALUATION The staff review of the licensee's request was perfomed in accordance with the guidelines of the Standard Peview Plan, section 3.9.6 and the ASME Boiler and Pressure Vessel Code Section XI.

Letters provided by the manufacturer indicate that the pu;pp and tu-bine can be safely operated at speeds up to and including 3800 rpm with no adverse effect.

The manufacturer has stated that the design for the pump turbine will not be affected at operation at or below 3800 rpn.

The docwentation provided 1,y the licensee verifies that the new speed represents acceptable pump operation. Prior to returning to power the licensee will test the CA pump turbine at the new speed in accordance with TS 4.7.1.2.la.2).

An additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is granted in order to perform these Since the pump will operate at higher speed limits, a new set of tests.

reference values per Table IWP 3100-1 of the ASME Code,Section XI, will be 8612010353 861120 PDR ADOCK 05000413 p

PDR I

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. developed through these tests prior to exceeding Mode 3, and used as accept-ance criteria for future inservice tests.

Inservice test quantities such as vibretion amplitude, differential pressure and flow rate will be measured ouarterly for this pump as part of the Catawba Inservice Test Program developed in accordance with Section XI of the ASME Code.

This change will be implemented by adjusting the rpm setting for the pump turbine governor to a specific value up to 3800 rpm to achieve the sarc re-quired total dynamic head under the same minimum conditions of flow and secondary steam supply pressure. The increased rpm adjustment would result in a slight increase in actual pump discharge flow and, thereby, enhance system safety perfomance. Although the pump and turbine would operate with reduced margin in the overspeed trip setpoints (4140 rpm for the electronic overspeed device), the available margin is indicated by the turbine manufacturer to be acceptable for satisfactory turbine operation.

Reset controls for the electronic overspeed device are located in the Control Room to alert the operator should reset be needed.

Therefore, the proposed rpm setpoint is not expected to result in a significant change in the possibility that the pump safety function would be defeated by exceeding overspeed; also, pump operation following actuation of the overspeed device can be quickly re-stored, if needed.

On the basis of our review and the requirement to establish new reference values per Para cludes that (1) graph IWP 3111 of the ASME Code,Section XI, the staff con-the change will not degrade the pump / turbine, (2) the required head and flow will continue to perfonn the safety function, and (3) the licensee will cortinue to test the CA pump turbine in accordance with the Section XI of the Code and the Technical Specification as revised. The staff also finds that the requested one-time extension, by 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, of the tire allowed to remain in Mode 3 in order to retest at the new rpm value, is appropriate considering the safety significance of such operation.

Ill.

ENVIRONMENTAL CONSIDERATION These amendments involve a change to the use of facility components located within the restricted area as defined in 10 CFR Part 20 and in surveillance requirements. The staff has determined that the amendments involve no signi-ficant increase in the amounts, and no significant charge in the types, of any effluents that may be released offsite and that there is no significant j

increase in individual or cumulative occupational radiation exposure. The Comission has made a final no significant hazards consideration finding with respect to the amendments. Accordfogly, the omendments 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 assess-ment need be prepared in connection with the issuance of these amendments.

IV. FINAL N0 SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION The State was infonned by telephone on November 13, 1986, of the staff's no significant hazards censideration determination. The State contact had no comments on the octermination.

.0 The staff has reviewed the licensee's request for the above amendments and de mined that should this request for the above acendments be implemented, it wo not (1) involve a significant increese in the probability or consequences of an accioent previously evaluated because the temporary unavailability of the turbine-driven pump (whether as a result of overspeed trip or the extension b 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of the allowed period for the reactor to remain in Mode 3 to repeat the test) has no effect on the most severe accident (i.e., feedwater system pipe break) previously evaluated by the staff in Section 15.3.3 of the Catawba SER MIPEG-0954 In this accident a double-enacd rupture of the largest feedwater line was assumed.

The turbine-driven auxiliary feedwater pump is assumed to fail and all ficw from one of the two motor-driven pumps spills out through the break.

The flow from the other motor-driven pump would supply the two intact steam generators.

that accident were acceptable.The staff concluded in NUREG-0954 that the con In addition, the proposed change would allow the turbine-driven pump to better fulfill its intended function during an accioent and thus would potentially decrease the consequences of an accicent.

Also, it would not (2) create the possibilit3 of a new or different kind of accident from any accident previously evaluated because the only effect of the change is on the availability and capability of the turbine-driven feedwater pump and, as discussed above, for the accident of relevance (the failure of a feedwater line) the turbine-driven feedwater pump is assumed to fail.

In addition, operation of the auxiliary feedwater turbine-driven pump at the increased speed has been evaluated by the manufacturer and found acceptable and because the proposed change introduces no new mode of operation (only a slightly higher operating speed) and no physical modifications (other then adjustment of the pump turbine governor).

Finally, it would not (3) involve a significant recuction in a margin of safety because, while the temporary unavailability of the turbine-driven auxiliary feedwater pump would slightly reduce the safety margin, this reduction has been detemined not to be significant in light of the accident evaluation discussed above.

In addition, the increase in pump speed and the accompanying increase in the actual turbine-driven pump discharge flow would allow the pump to 'better perfom its safety functions and the slight decrease in margin to the overspeed trip setpoints is not deemed significant and the pump can be promptly reset if needed.

Accordingly, the Comission proposes to find that the change does not involve a significant hazards consideration.

V.

FINDINGS OF EMERGENCY WARRANTING AN AMENDPENT WITHOUT NOTI The licensee's application fer the Technical Specification change has been timely.

The licensee states that it was only recently recognized that addi-tional operating margin might be needed in crder for the turbine-driven auxiliary feedwater pumps to reet requirements. The first request by letter dated October 27, 1986, was submitted in anticipation of the need for in-creased flexibility to reet TS reouirements. The licensee's request for emergency amendnents resulted from surveillance tests in accordance with TS 4.7.1.2.la.?).

The test for Unit 2 was conducted on hovember 12, 1986 as the unit was returning from a maintenance outage and upon reaching Mcde 3.

At 3600 rpm, the Unit 2 pump produced slightly less than the required head and the pump was declared inoperable.

1:ithout these amendments, the Unit 2 pump wculd have to be returned to operable status by C305 hours.on November 14, l

1986, or the unit would have to be cooled down to Mode 4 Catawba Unit I was similarly tested on November 13, 1986, and also did rot mcct the acceptance criteria.upon returning from a refueling cetece, Without these amendments, the Unit 1 pump would have to be returned to operable status by JP45 hours on

. 4 November 13, 19P6, or the unit would have to be cooled down to Mode 4.

The requested change provides for an increase in the developed head sufficient to n+et the Technical Specification requirements.

The change also requires that an aoditional time for operation in Pode 3 be allowed, on a one-titre basis, in order to obtain neasurements required by ASME Code,Section XI when pump / turbine parameters are chanced.

The licensee contacted the L'RC staff promptly after the test results were obtained. Since the need for emergercy action arises fron results of tests which must be perfortcd with the plant in Mode 3, the licensee could not have reasonably avoided this situation.

The staff finds thct feilure to grant the proposed change in a timely manner would increase the outage time of the units.

We also find that the licensee could not reasonably have avoided this situation, that the licensee has re-sponded in a timely manner, and has not delayed its application to take advantage cf the Emergency License Amendments provisions of 10 CFR 50.91.

Accordingly, the staff concludes that the licensee has satisfied the require-ments of 10 CFR 50.91(a)(5), and that a valid emergency exists.

VI. CONCLUSION 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 Commission's regulaticns, and (3) the issuance of these amendments will not be inimical to the conson defense and security or to the health and safety of the public.

Principal Contributors:

Kahtan Jabbcur, PWR#4 Darl Hood, PWR*4 Kenneth Denpsey, PAEB Dated: November 20, 1986