ML20198S728

Safety Evaluation Supporting 851203 Proposal to Modify Tech Spec 3/4.5.3 to Clarify Min Amount of Condensate Storage Tank Water Required to Ensure Operability of Core Spray Sys During Operating Conditions 4 or 5.Rev to Tech Specs Encl

ML20198S728
Person / Time
Site:	Brunswick
Issue date:	05/29/1986
From:	Office of Nuclear Reactor Regulation
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ML20198S721	List: ML20198S716 ML20198S728
References
NUDOCS 8606100545
Download: ML20198S728 (4)

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UNITED STATES 4g

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5 j NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION BASES TO TECHNICAL SPECIFICATION 3/4.5.3.1, " CORE SPRAY SYSTEM (CSS)"

BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 DOCKET N05. 50-325/324

1.0 INTRODUCTION

In a letter dated December 3, 1985, the Carolina Power and Light Company requested a change in Technical Specification (TS) bases relating to the core spray system for the Brunswick Steam Electric Plant, Unit Nos. I and

2. The proposed change to the bases for TS 3/4.5.3.1 serves to clarify the minimum condensate storage tank (CST) volume required for the operability of the core spray and the HPCI/RCIC system.

2.0 EVALUATION During a recent review of TS 3/4.5.3.1, a question arose as to whether the 150,000 gallon core spray requirement coupled with the 100,000 gallon HPCI/RCIC requirement constituted a combined minimum requirement for the condensate storage tank of 250,000 gallons. After a review of the system's requirements, the licensee verified that 150,000 gallons was the total minimum requirement for the tank. Of this, 50,000 gallons were required for the core spray system (CSS) operability requirements and 100,000 gallons for the HPCI/RCIC requirements.

There is no ambiguity as to the 100,000 gallons for the HPCI/RCIC requirement since the CSS suction is at the 100,000 gallons level. The question is whether 50,000 gallons or 150,000 gallons is required for i core spray system operability. The core spray system can take suction either from the suppression pool or the condensate storage tank, with the latter providing the CSS with a source of demineralized water for injection path testing in conditions 4 and 5 during a reactor shutdowr..

In conditions 1, 2 and 3 when the CSS is required to be operable the valves from the CST to the CSS pumps are locked shut and the CSS takes suction form the suppression pool. Assuming each of the two CSS Pumps has a capacity of 5000 gpm, the 50,000 gallons in the CST could last for about 5 minutes if both CSS pumps operate at full capacity. This duration is deemed adequate for the injection path testing in conditions 4 and 5 were there no accidental draining of vessel water. In the event of such an accidental draining when the CSS is not available for core cooling, adequate assurance of core flooding is provided by one low pressure coolant injection (LPCI) loop. Therefore, it is concluded that the risk posed to the public health and safety as a result of the postulated event 8606100545 DR 860529 ADOCK 05000324 PDR

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is very low. This change to the bases for TS 3/4.5.3.1 is deemed i

consistent witt the requirements in the current Technical Specifications that involve the Reactor Protection System and is also consistent with the requirements for the ECCS in the Standard Technical Specifications for the BWR/4's.

3.0 CONCLUSION

Based on our review, we concur with the licensee that the proposed change to the Bases for Technical Specification 3/4.5.3.1 is appropriate and necessary to clarify the operability requirements for the core spray system in operational conditions 4 and 5.

Principal Contributor: D. Yue Dated: May 29,1986 I

4 EMERGENCY CORE COOLING SYSTEMS BASES AUTOHATIC DEPRESSURIZATION SYSTEM (Continued)

ADS automatically controls 7 safety-rel~ief valves although the hazards analysis only takes credit for 6. It is therefore appropriate to permit one ,

' valve to be out-of-service indefinitely without materially reducing system reliability. Reactor operation is permitted to continue for up to 7 days with 2 safety-relief valves inoperable except that HPCI is required to be demonstrated to be OPERABLE.

The surveillance requirements provide adequate assurance that ADS will be OPERABLE when required. Although all active components are testable during reactor operation, a complete functional test results in reactor blowdown and therefore is scheduled around shutdowns.

3/4.5.3 LOW PRESSURE COOLING SYSTEMS 3/4.5.3.1 CORE SPRAY SYSTEM (CSS)

The CSS is provided to assure that the core is adequately cooled following

a loss-of-coolant accident. Two redundant loops each provide adequate core

cooling capacity for all break sizes from 0.2 ft2 up to and including the double-ended reactor recirculation line break, and for smaller breaks following depressurization by the ADS.

The CSS specifications are applicable during CONDITIONS 1, 2, and 3 -

because CSS is a primary source of emergency core cooling after the reactor vessel is depressurized.

When in CONDITION 1, 2, or 3 with one CSS Loop inoperable, the

-l demonstraced OPERABILITY of the redundant full capacity CSS loop and the full capacity Low Pressure Coolant Injection System provides assurance of adequate

core cooling and justifies the specified 7-day out-of-service period.

f The CSS specifications are applicable in CONDITIOUS 4 and 5 to provide a source for flooding of the core in case of accidental draining.

The specified volume of 150,000 gallons of water in the condensate storage

. tank will assure the availability of 50,000 gallons of water for the CSS since

- l its suction is at the 100,000 gallons level. The 100,000 gallons is the

. minimum reserved for HPCI/RCIC operation.

1 BRUNSWICK - UNIT 1 B 3 4 5-2 Revised ltr 5/29/86

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EMERCENCY CORE COOLING SYSTEMS BASES AUTOMATIC DEPRESSURIZATION SYSTEM (Continued)

ADS automatically controls 7 safety-relief valves, although the hazards

, analysis only takes credit for 6. It is therefore appropriate to permit one valve to be out-of-service indefinitely without materially reducing system reliability. Reactor operation is permitted to continue for up to 7 days with 2 safety-relief valves inoperable except that HPCI is required to be demonstrated to be OPERABLE.

The surveillance requirements provide adequate assurance that ADS will be OPERABLE when required. Although all active components are testable during reactor operation, a complete functional test results in reactor blowdown and, therefore, is scheduled around shutdowns.

3/4.5.3 LOW PRESSURE COOLING SYSTEMS 3/4.5.3.1 CORE SPRAY SYSTEM (CSS)

The CSS is provided to assure that the core is adequately cooled following a loss-of-coolant accident. Two redundant loops each provide adequate core cooling capacity for all break sizes from 0.2 ft2 up to and including the double-ended reactor recirculation line break, and for smaller breaks following 4epressurisation by the ADS.

The CSS specifications are applicable during CONDITIONS 1, 2, and 3 because CSS is a primary source of emergency core cooling after the reactor vessel is depressurized.

When in CONDITIONS 1, 2, or 3 with one CSS loop inoperable, the demonstrated OPERABILITY of the redundant full capacity CSS loop and the full capacity Low Pressure Coolant Injection System provides assurance of adequate core cooling and justifies the specified 7 day out-of-service period.

i The CSS specifications are applicable in CONDITIONS 4 and 5 to provide a source for flooding of the core in case of accidental draining.

The specified volume of 150,000 gallons of water in the condensate storage tank will assure the availability of 50,000 gallons of water for the CSS since its suction is at the 100,000 gallons level. The 100,000 gallons is the minimum reserved for HPCI/RCIC operation.

BRUNSWICK - UNIT 2 B 3/4 5-2 Revised ltr 5/29/86

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