ML20209C943

Discusses Status of Accident Evaluation Branch Final SER Input.Concerns Re Containment Spray Sys Resolved.Control Room Habitability Sys Unresolved

ML20209C943
Person / Time
Site:	Satsop
Issue date:	05/11/1984
From:	Muller D Office of Nuclear Reactor Regulation
To:	Novak T Office of Nuclear Reactor Regulation
References
CON-WNP-1451 NUDOCS 8405210567
Download: ML20209C943 (5)

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.N 34 5 Q Siy a Docket No. 50-508 D MEMORANDtM FOR: Thomas M. Novak, Assistant Director for Licensing, DL FROM: Daniel R. Muller, Assistant Director for Radiation Protection, OSI -

SUBJECT:

FINAL SER INPUT FOR WASHINGTON FU3LIC POWER SUPB./ SYSTEM, UNIT 3 PLANT NAME: Washington Nuclear Plant, Unit 3 LICENSING STAGE: OL RESPONSIBLE BRANCH: LB#3; A. Vietti, LPM REQUESTED COMPLETION DATE: June 15,1984 REVIEW STATUS: Continuing By memorandum dated October 31, 1983, the Accident Evaluation Branch IAEB) supplied input for the draft safety evaluation report (SER) which included sections on Centrol Room Habitability (Section 6.4), Containment Spray as a Fission Product Control System (Section 6.5.2), and the Radiological Consequences of Postulated Design Bases Accidents (Section 15.X). In that draft SER, we identified two open items. These were control room habitability and the containment spray system.

l In response to AEB question 450.1 and Cnemical Engineering Branch Question 281.1, the applicant has supplied a detailed discussion of the

[ design and proposed operation of the chemical addition portion of the l containment spray system. AEB has reviewed this information and concludes

! that our previous concerns have been resolved. A revised SER Section 6.5.2 i is attached which resolves this open iten.

The applicant has not addressed the concerns about the control room habitability system expressed in the draft SER. Therefore, the control room habitability system remains as an open item.

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'I T. H. Novak Draft SER Section 15.X previously supplied in our October 31, 1983 memorandum, should be considered as final input. This AEB review was coordinated by Frank Akstulewicz (x24993).

SFIG inal atpe, Daniel R. Muller, Assistant Director for Radiation Protection Division of Systems Integration

Attachment:

As stated cc: R. Mattson G. Knighton W. Gammill A. Vietti DISTRIBUTION:

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5 S.5.2 Contain Spray As_ _A Fission Product Removal System The Containment Spray System consists of two independent and redundant loops, sacn consisting of a spray pump, shutdown heat exchanger, piping, valves, spray headers, and nozzles. With respect to fission product control, sodium

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hydroxide (NaOH) is to be injected into the spray system to promote the removal and ratention of airDorn6 iodine. The design is unique in that the cover gas dich is provided to preclude the' deterioration of the Na0H also s

provides the drhf ng force for the chemical addition into the spray system.

The containcent spra,y systein is to be automatically initiated upon receipt cf a Contsinnunt Spray Actuation Signal. 'The containment spray pumps take suction from the Refuelifig Wter Stcrage Tank (RWST). The Na0H is injected into the suction of the centainiiient spray pumps by the tank cover gas over pressura.at a rate which main.tains ths pump discharge fluid at a pH between I ,.5 and 11. Ocntrol of the chemical addition is performed by maintaining a constant ratio 'between the Na0H and containment spray flow rates. A flow control valve is used wnich is to be automatically modulated by the ratio control loop instru6entaticn. Toe control loop establishes the desired Na0H flow rate by using tne product 6f the pontainment spray pump flow signal i

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l .. and the ratio setpoint as the demand signal input in.to the NaOH flow controller. The NaOH flou controller then automatically modulates the flow control valves until any deviation is eliminated No operator action is required to manipulate the contro1 valve.

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l The chemical addition flow cor. trol system is alarmed in the control room if the .Na0H flow rate is less than 50 gpm or mera than 58 gpm. This provides added assurance that the injection pH of the spray fluid will be j between 8.5 and 11. -

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When a predetermined low level is raached in the RWST, the recirculation

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mode of the containment spray system is automatically' initiated by the recirculation. actuation signal (RAS). In this mode, the suction of the spray pumps are switched from the RWST to the containment sump:. ,The NaOH flow rate is automatically cdjusted to maintain the pH within the proper range.

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Injection of NaOH continues until a preset low level is reached in the Chemical Storage Tank. , Upon reeching this level, a signal is generated which automatically closes the injection is'olation valves and terminates chemical injection. ,

The staff concludes that the containment spray system as a fission product cleanup system is acceptable and meets the relevant' requirements of GDC 41,

" Containment Atmosphere Cleanup;" 42, " Inspection of Containment Atmosphere Cleanup Systems;" and 43, " Testing of Containment Atmosphere Cleanup Systems."

This conclusion is based on the following: The concept on which the. proposed

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system is based has been demonstrated to be effective for iodine absorption <

and retention under postaccident conditions. The proposed system design r .. : ,

.. is an acceptable application of this concept. The system prwides suitable redundancy in components and features, or its safety function can be

accomplished assuming a single failure. The staff concludes that the system meets the requirements of GDC 41. '

The proposed preoperational tests, postoperational testing and surveillance, and proposed limiting conditions of operation for the spray system provide

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adequate assurance that the iodine scrubbing function of the containment spray system will meet or exceed the effectiveness assumed in the accident

.. evaluation. Therefore, it meets the requirements of GDC 42 and 43.

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