ML20198S780

Safety Evaluation Supporting Amend 223 to License DPR-65

ML20198S780
Person / Time
Site:	Millstone
Issue date:	12/31/1998
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20198S776	List: ML20198S780
References
NUDOCS 9901120004
Download: ML20198S780 (3)

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NUCLEAR REGULATORY COMMISSION

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WASHINGTON, D.C. E1eH001 SAFETY EVALUATION PY THE OFFICE OF NUCLEAR REACTOR REGULATION i

I RELATED TO AMENDMENT NO. 22 4 TO FACILITY OPERATING LICENSE NO. DPR-65 NORTHEAST NUCLEAR ENERGY COMPANY l-THE CONNECTICUT LIGHT AND POWER COMPANY U

THE WESTERN MASSACHUSETTS ELECTRIC COMPANY MILLSTONE NUCLEAR POWER STATION. UNIT NO. 2 l

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DOCKET NO. 50-336 l

1.0 INTRODUCTION

By letter dated August 4,1998, the Northeast Nuclear Energy Company, et al. (the licensee),

L submitted a request for changes to the Millstone Nuclear Power Station, Unit No. 2 (MNPS-2) i Technical Specifications (Tbs). The requested changes would change the TS requirements l

relating to the condensate storage tank (CST) and also add a new TS that would establish l.

requirements for the atmospheric steam dump valves (ASDVs) to assure their operability. The L

applicable TS Bases for the CST would also be modified to reflect the proposed changes and a new TS Bases Section would be added to discuss the new TS for the ASDVs.

2.0 EVALUATION i

The first portion of the amendment request would modify TS 3.7.1.3, " Plant Systems -

Condensate Storage Tank," by increasing the minimum required CST level from 150,000 gallons to 165,000 gallons to account for the discharge nozzle pipe elevation above

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the tank bottom and vortex formation occurring in the CST at the auxiliary feedwater (AFW) j system supply piping entrance.

The CST is required to maintain an adequate volume of water for the following three conditions, to: (1) remove decay heat and sensible heat to cool down the plant to less than

^ 300 'F following a loss of offsite power (LOOP) event; (2) remove only decay heat to maintain

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the plant in's hot standby condition for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />; and (3) remove decay heat and sensible heat to be able to cope with an 8-hour station blackout (SBO) event.

L Conditions 1 and 3 require 136,000 gallons of water and Condition 2 requires 115,000 gallons of water. These requirements are well within the current TS requirement of 150,000 gations; however, there is an unusable volume of water in the CST due to the location of the discharge j

nozzle and vortex formation occurring in the CST where the AFW system supply piping enters.

9901120004 981231 i

PDR ADOCK 05000336 F

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-a 2-t The licensee has determined that the unusable volume of water due to the location of the discharge nozzle is approximately 15.000 gallons and the unusable volume of water due to the vortex formation is approximately 8,000 gallons for a total volume of 23,000 gallons of unusable water in the CST. Conditions 1 and 3 require a total CST volume of 159,000 gallons of water and Condition 2 requires 138,000 gallons of water when the unusable water in the CST is taken into consideration. Thus, the current requirement of 150,000 gallons is not adequate for Conditions 1 and 3. The applicable TS Bases section will be updated to reflect the proposed change in the CST water volume to account for the unusable stored water.

The proposed change to TS 3.7.1.3 will increase the minimum allowable volume of water in the CST to 165,000 gallons, which bounds the amount of water needed for the conditions noted above, and also includes a margin of about 6,000 gallons. This change is well within the total capacity of the CST, which is 250,000 gallons, and the TS required volume of water will be stored within the missile protected portion (205,000 gallon-level) of the CST.

Therefore, the NRC staff has determined, based on the previous discussion, that the proposed change to TS 3.7.1.3 relating to the required minimum water volume in the CST is acceptable.

The updated TS Bases adequately reflect the proposed TS change.

The second portion of the request would add a new TS section, TS 3.7.1.7, " Plant Systems -

Atomospheric Steam Dump Valves," to provide the requirements necessary to assure that the ASDVs will be available to remove heat from the reactor coolant system (RCS) to either maintain the unit in hot standby or cool down the unit to shutdown cooling (SDC) entry i

conditions if the condenser steam dump valves are not available.

i The atmospheric steam dump system at MNPS-2 consists of one ASDV for each of the two steam generators..The design does not include remotely controlled block valves to isolate the ASDVs, however, each of the ASDVs can be isolated by a local manually controlled isolation valve.

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Proposed TS 3.7.1.7 requires each of the two ASDVs to be operable in Modes 1,2, and 3. If one ASDV is inoperable, it has to be restored to operable within 7 days or be in Mode 3 in the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 4 within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. If both the ASDVs are inoperable, one has to be restored to operable within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in Mode 3 within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Mode 4 within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> reflects the potentialimpact on plant cooldown time with one or both ASDVs inoperable.

Proposed TS 4.7.1.7 requires that one complete cycle of each ASDV be verified at least once per 18 months.

Proposed TS 3.7.1.7 and TS 4.7.1.7 constitute additionallimitations, restrictions, or controls not presently included in the TSs, and are consistent, to the extent practical, with the guidance provided in NUREG-1432, Rev.1, " Standard Technical Specifications Combustion Engineering Plants," dated April 1995. The proposed TSs are, therefore, acceptable. The new TS Bases, 3/4.7.1.7, adequately reflect the new TSs.

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! 3.0 STATE CONSULTATIO.f3 in accordance with the Commission's regulations, the Connecticut State official was notified of the proposed issuance of the amendment. The State official had no comments.

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4.0 ENVIRONMENTAL CONSfDERATION The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendment involves no l

significant increase in the amounts, and no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (63 FR 45526 dated August 26,1998). Accordingly, the amendment meets 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 i

p'epared in connection with the issuance of the amendment.

5.0

' CONCLUSION 1

The Commission 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, (2) such activitiet. sill be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

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Principal Contribution:

D. Mcdonald Date:

December 31, 1998 l

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