ML20244D862

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Forwards Plant Sys Branch Sser Input Re Section 6.8, Emergency Feedwater & Section 9.5.4.1, Emergency Diesel Engine Auxiliary Support Sys (General). SALP Input Provided in 860426 Memo Also Applicable to Input
ML20244D862
Person / Time
Site: Seabrook, 05000000
Issue date: 05/12/1986
From: Rossi C
Office of Nuclear Reactor Regulation
To: Nerses V
Office of Nuclear Reactor Regulation
Shared Package
ML20235T530 List: ... further results
References
FOIA-87-51, RTR-NUREG-0896, RTR-NUREG-896 NUDOCS 8605200021
Download: ML20244D862 (6)
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Text

. docketNos: 50 443, 50-444 DISTRIBUTION i MAY 121906 Docket File MEMORANDUM FOR: V. Nerses, Senior Project hanager PSB Docket File )

PWR Project Directorate #5 PSB Reading File Division of PWR Licensing - A R. Giardin Q _ __-

J. Shapaker FROM: Charles E. Rossi, Assistant Director J. Milhoan for PWR.A C. Rossi Division of PWR Licensing - A i 1

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SUBJECT:

SEABROOK STATION, UNITS 1 AND 2, INPUT FOR SUPPLEMENT TO THE SAFETY EVALUATION REPORT Plant Name: Seabrook Station, Units 1 and 2 Utility: Public Service Company of New Hampshire Docket Nos.i 50-443 and 50 444 Project Manager: V. Nerses Review Branch: Plant Systems Branch Review Status: Awaiting Information l l

The attached input for the Seabrook Station, Units 1 and 2 Supplemental Safety I Evaluation Report (SSER) was prepared by the Plant Systems Branch (DPL.A). The evaluations pertain to Section 6.8, Emergency Feedwater, and Section 9.5.4.1, Emergency Diesel Engine Auxiliary Support Systems (General). The SALP input l

provided in the April 26, 1986 memorandum is also applicable to this SSER input. l Crisitti si~ odEy] .

Charles E. Rossi, Assistant Director for PWR.A Division of PWR Licensing - A

Enclosure:

As stated cc: T. Novak O. Parr V. Noonan L. Hulman R. Bosnak

Contact:

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'4 Supplemental Safety Ev'aluation Report l Seabrook Nuclear Station, Units 1 and 2 Docket Nos. 50-443 and 50-444 Plant Systems Branch 6.8 Emergency Feedwater System l

During the perfonnance of the Emergency Feedwater (EFW) System hot functional tests, performance problems were experienced with the EFW steam supply lines and the EFW recirculation system. The problems encountered were described in IE Inspection Report Numbers 50-443/85-30 and 50-443/85-31, dated December 31, 1985, and in applicant letters dated April 1,1986 and April 16, 1986. Four problems were identified:

1. EFW Stbam Supply Isolation Valves (MS-V127 and MS-V128) did not operate as expected. The valves are supposed to open simultaneously upon receipt of an EFW initiation signal. However, due to the valve type (gate valve) and the high differential pressure across the valves (1100 psi), the valves did not open simultaneously.
2. As a result of valves MS-V127 and MS-V128 not opening properly and prior incomplete draining of condensate from the steam line, a waterhar:rner occurred in the line to the EFW turbine driven pump.
3. The design configuration of each EFW pump minimum flow recirculation line provided for continuous recirculation from the EFW pump discharge
  • to the alternate EFW pump suction. This resulted in high EFW pump suction temperatures.
4. The recirculation line design (item 3 above) also resulted in insufficient flow to the steam generators due to excessive recirculation line flow.

By letters dated April 1, 1986 and April 16, 1986, the applicant described the EFW system modifications that will be made to correct the above problems.

The design changes are as follows:

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1. EFW Steam Supply Isolation . Valves MS-V127 and MS-V128 will remain in the system, but will normally be kept open. Remote manual control from the main control room will be available to close these valves

-in the event of a steam generator tube rupture, as specified in the plant operating procedures. Two new air-operated, globe-type valves (MS-V393 and MS-V394) will be installed downsteam of MS-V127 and MS-V128 to serve as isolation valves. These valves will' open simul-taneously on an EFW initiation signal and, on loss of power, will fail in the open position. On opening, the valves admit steam to the

!* steam supply header and valve MS-V395. Valve MS-V395 has a delayed opening following the opening of either MS-V393 or MS-V394, to allow for thb pressurization of the steam header and the discharge of accumulated condensate, prior to the introduction of steam to the turbine governor valve. The elapsed time from an EFW initiation signal 'to MS-V395 being fully open is approximately 35 seconds. The staff finds the valve changes to be a reasonable approach to resolving the valve sticking problem.

2. The EFW steam supply lines have been resloped t.o provide a continuous declination to newly installed drain assemblies. This resloping of the lines along with the modifications discussed above should eliminate potential waterhammer problems.

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3. With respect to problems 3 and 4 identified above, the EFW pump minimum -
  • flow recirculation line has been redesigned. A new recirculation line i i

will be installed from each EFW pump discharge to a common header which  ;

will return the recirculation flow to the condensate storage tank. Each  ;

pump recirculation line will have a normally closed, motor-operated valve. l These valves will be administrative 1y controlled so that the required flow to the steam generators is assured for all operating conditions. Upon recovering steam generator water level, the plant operating procedures l specify that the minimum flow recirculation line isolation valves should I be opened prior to throtting EFW flow to the steam generators. The new recirculation lines will be designed to Seismic Category 1, ASME Code, B

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Section III, Class 3 requirements, and will be tornado missile protected. The staff finds this acceptaDie.

i Based on the foregoing evaluation, the staff finds the EFW system design changes )

and changes in operating procedures to be responsive to the problems encountered during hot functional testing of the EFW system, and to provide reasonable assurance that the EFW system will perfonn its design safety function.

l 9.5.4.1 Emergency Diesel Engine Auxiliary Support Systems (General)

The Seabrook, SER (NUREG-0896, dated March 1983) states that based on the diesel engine manufacturer's (Colt Industries) statements and recommendations, the applicant committed to install a preheater in the combustion air intake plenum to alleviate the staff's concern on no load operation at extremely low ambient temperatures. The staff found the design acceptable provided:

1. The electrical aspects of the design (no load operation), evaluated in Section 8.3.1.2.8 of the SER, are acceptable, and
2. The following periodic inspection would be included in the technical I specifications: ,

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" At least once per 31 days verify the operability of the air .

s intake preheaters and their power and control circuitry. In-operability of the air preheat system will constitute a failure of the diesel generator and the diesel generator will be subject to the limiting condition of operation."

By letters dated February 14, 1983, November 27, 1985, and April 11, 1986, the applicant stated that preheaters were not necessary based on information from the manufacturer. The staff evaluated the manufacturer's argument that the diesel generator is capable of operating at no-load and low ambient temperatures for L__ _ _ _ _ _ _ .

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-4' up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> before the engine must be loaded to clear the exhaust stacks of deposits. Based on the manufacturer's discussion, the staff concurs that the preheaters are not necessary for operation of the diesel generator and that they can be removed. In addition, the above technical specification requirement may be deleted.

In Section 8.3.1.2.8 of Supplement 4 to the SER it is stated that based on test results the staff concludes that the Seabrook diesel generators are capable of accepting design load after operation at no-load for six hours. Based on the test results, the no-load / light load operating procedures stated in the SER should be changed to read as follows:

2 (1) During extended no-load and light-load operation (less than 20% full load),

the diesel will be loaded to a minimum of 50% of full load for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> following each 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> of continuous no-load or light-load operation.

(2) During periodic testing, the diesel will be loaded to a minimum of 25% of full load or as recomended by the manufacturer.

(3) During troubleshooting, no-load operation will be minimized. If the troubleshooting operation takes place over an extended period of time (i.e., 3 to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or more), the engine will be cleared by loading the diesel to a minimum of 25% of full load for at least 30 minutes. -

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l CONTAINMENT SYSTEMS s I

f PRIMARY CONTAINMENT CONTAINMENT AIR LOCKS SURVEILLANCE REQUIREMENTS l

l 4.6.1.3 Each containment air lock shall be demonstrated OPERABLE:

a. Within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following each closing, except when the air lock is being used for multiple entries, then at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, by verifying that the seal leakage is less than 0.01 L as determined 3

by precision flow measurements when measured for at least 30 seconds '

within the volume between the seal at a constant pressure of 49.6 psig; b.

By conducting overall air lock leakage tests at not less than P,,

49.6 psig, and verifying the overall air lock leakage rate is within its limit:

1) At least once per 6 months,* and l
2) Prior to establishing CONTAINMENT INTEGRITY when maintenance has been performed on t air lock that could affect the air lock sealing capabilit .

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c. At least once per 6 months by verifying that only one door in each air lock can be opened at a time.

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  • The provisions of Specification 4.0.2 are not applicable.
    • This represents an exemption to Appendix J, paragraph III.D.2.(b)(ii),

of 10 CFR Part 50.

SEABROOK - UNIT 1 3/4 6-8

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