ML20215D291

Application for Proposed Amend 129 to License DPR-54, Revising Tech Specs to Clarify Difference of Air Flow Rates Through Reactor Bldg Purge Valves W/ or W/O Containment Integrity.Fee Paid

ML20215D291
Person / Time
Site:	Rancho Seco
Issue date:	12/12/1986
From:	Julie Ward SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Miraglia F Office of Nuclear Reactor Regulation
Shared Package
ML20215D293	List: ML20215D291 ML20215D308
References
JEW-86-219, NUDOCS 8612160306
Download: ML20215D291 (5)

Text

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(SMU= SACRAMENTO MUNICIPAL UTILITY DISTRICT : ~ 6201 S Street. P.o. Box 15830. Sacramento CA 95852 1830,(916)452 3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA JEW 86-219 December 12, 1986 DIRECTOR OF NUCLEAR REACTOR REGULATION ATTENTION FRANK J MIRAGLIA DIRECTOR PWR-B DIVISION U S NUCLEAR REGULATORY COMMISSION WASHINGTON DC 20555 DOCKET N0. 50-312 LICENSE NO. DPR-54 PROPOSED AMENDMENT NO. 129 In accordance with 10 CFR 50.90, the Sacramento Municipal Utility District proposes to amend its Operating License DPR-54 for Rancho Seco Nuclear Generating Station Unit No. 1.

Proposed Amendment No. 129 provides clarification in Specification 4.11.1A and the Bases that the air flow rate through the Reactor Building Purge Valves is different with and without conditions of containment integrity.

This proposed amendment also adds Specification 4.11.D.2.(b) which through oversight, was not included in a previous amendment.

Details of this proposed amendment are presented in Attachments I, II and III which are the Safety Analysis, "No Significant Hazards" Evaluation and Description of Proposed Changes, respectively.

Pursuant to 10 CFR 50.91(b)(1), the Radiological Health Branch of the California State Department of Health Services has been informed of this proposed amendment by mailed copy of this submittal.

Enclosed is a check in the amount of $150.00 as required by 10 CFR 170.21,

" Schedule of Fees."

Should you require any further information with respect to this Proposed Amendment, please contact Mr. Ron Colombo at Rancho Seco Nuclear Gen-erating Station Unit No. 1.

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( M WARD Subscribed and sworn to before me ASSISTANT GENERAL MANAGER this [ day of Decembc(, 1986 NUCLEAR Attachments cc: Region V (2) n (Utlvv1C IP (2) m OFFICIAL SEAL I DAWN DARUNG \g 8612160306 061212 12 PDR ADOCK 050 g{d f/in,iffiOTARyPUBUC

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ATTAC E NT I SAFETY ANALYSIS Technical Specification 4.11.1A requires that the operational characteristics of the HEPA and charcoal filter banks associated with the Reactor Building Purge System be tested at least once 30 days prior to the start of fuel han-dling in the Reactor Building. Under the present specification, the air flow rate through the filter train is adjusted to maintain 66,700 CFM i 10% during containment integrity conditions with between 2 and 6 inches water gauge pressure drop across the combined HEPA and charcoal filter banks.

In response to the valve manufacturers recommendations (Allis-Chalmers Report A-C,VER0209,12/17/79), the Reactor Building Purge System inboard valves (SFV 53504 and SFV 53605) were modified to limit valve opening positions such that adequate closing torques would be maintained while limiting stresses below recommended operating levels. The inboard purge valves were modified to limit their strcke angle to .c 80* of their full open positions, and the outboard purge valves limited to g 60 of their full open positions.

As a result of these reduced valve stroke angles, the air flow rate of 66,700 cfm i 10% specified in 4.11.1A for flow through the HEPA filter and charcoal absorber train cannot be achieved with the required pressure drop across the combined filter banks. The flow rate of 60,000 cfm i 10% submitted in this proposed amendment has been proven achievable by actual test.

Systems, Subsystems, Components Affected Proposed Amendment No. 129 affects only the Reactor Building Purge Filtering System's ability to be properly tested per specification 4.11.1A. No modif-ications to the existing system, its components or any subsystems are being croposed under this amendment.

Safety Functions Of Affected Systems / Components When in operation, the purge system processes Reactor Building air through the filtration system prior to release to the atmosphere. The discharge is monitored and activates a radiation monitoring system alarm in the event of excessive radioactivity (USAR 9.7.2.1.3). In the event of a postulated Fuel Handling Accident within the Reactor Building during the refueling mode, the purge valves perform a containment isolation function actuating on high radi-ation signal. In the event of a LOCA, closure of the purge valves to isolate the containment is initiated upon SFAS signals (USAR 9.7.2.1.4). However, the purge valves are maintained closed except during cold shutdown and refueling conditions per Technical Specification 3.6.7.

Effects on Safety Functions Surveillance Specification 4.11.1A along with other Section 4.11 specifica-tions demonstrate the required operability of the Reactor Building Purge Filtration system. The use of this system is restricted to the cold shutdown and refueling modes per Technical Specification 3.6.7, consistent with SRP 6.2.4 and BTP CSB 6-4. For the postulated LOCA, the system would not be in operation, with the inboard and outboard purge valves already in a closed

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position prior to the LOCA. The proposed decreased filtration air flow rate (66,700 CFM i 10% to 60,000 CFM i 10%) would have no effect on the USAR ana-lysis for the LOCA.

For the postulated Fuel Handling Accident within the Reactor Building, the radiation monitoring system high radiation signal would initiate the closure of the purge valves. With the lower proposed 60,000 CFM i 10% air flow rate prior to the valve closure, residence time within the HEPA and charcoal fil-tration cycle would be longer, therefore potentially reducing radiation levels released to the atmosphere prior to complete isolation.

Analysis of Effects on Safety Functions The proposed reduction for the purge system flow rate specification during surveillance testing has no effect on the isolation function (closure times) of the inboard and outboard purge valves. The valves continue to close within the specified times, consistent with the assumptions of the Chapter 14 Analyses. Due to the reduction of the air flow rate through the systen,, re-sidence time in the filtration cycle is longer, therefore potentially reduc-ing radiation releases to the atmosphere. There are no new failure modes being introduced as a result of the change.

Sunmary The proposed technical specification change affects only the adjustment of the air flow rate of the filtration system during the required surveillance testing. The fil'fation system's ability to process reactor building air is not degraded, nor is the containment isolation function of the purge valves affected by the reduction of flow. The proposed change allows the required surveillance test to be performed, consistent with the capability of the system. Implementation of the proposed amendment to Specification 4.11.1A does not constitute an unreviewed safety question.

On the basis of the above safety analysis, the District concludes that the proposed amendment will have no adverse effect on the safety of the plant, nor will the safety and health of the public be endangered.

i

ATTACl#ENT II

. "N0 SIGNIFICANT HA7.ARDS" EVALUATION

.Pr'oposed Amendment No. 129 consists of two adainistrative changes being made to Specification 4.11.1 of the Rancho Seco Technical Specifications.

The first change introduces a second flow rate (of 60,000 cfm i10%) to the 66,700 cfm i10% presently shown in Specification 4.11.1 that is exhausted from the Reactor Building Purge Valves. The two values represent the flow rate for the two conditions of 1) containment integrity, and 2) without con-tainment integrity. Calculations have confirmed that at either purge flow .

rate, the FSAR analysis for a loss of coolant accident (LOCA) remains valid.

Therefore, this proposed change is considered purely administrative.

lhe second change adds Specification 4.11.10.2.(b) which is identical to Specifications 4.10.1C.2.(b) and 4.12.20.2.(b) but which through oversight was not included in a previous amendment. This change also, is considered purely administrative.

The District has reviewea the proposed changos against each of the criterion of 10 CFR 50.92 and concluded that the clarification made to Specification 4.11.1A and the addition of Specification 4.11.10.2(b) plant operation would not:

a. involve a significant increase in the probability or consequences of an accident previously evaluated. As stated above, calculations with respect

. to the first change have confirmed that neither the existing nor the proposed exhaust flow rates from the Reactor Building Purge Valves will invalidate the FSAR analysis for a loss of coolant accident. The pro-posed change is judged to be purely administrative, providing clarifica-tion to the Technical Specifications. _

The second change, adding Specification 4.11.10.2.(b), corrects a previous oversight of omission, and is judged also as purely administrative.

As administrative changes, neither of the two proposed are seen as in-volving a significant increase in the probability or consequences of an accident previously evaluated.

b. create the possibility of a new or different kind of accident from any previcusly analyzed. Neither of the proposed changes introduce new plant designs or affect plant operations._ Therefore, the creation by these

proposed administrative changes of a new or different accident from any l

previously analyzed is not foreseen.

c. involve a significant reduction in a margin of safety. As stated in b.)

above, neither of the proposed changes affect plant design or operations.

Consequently, safety margins are not seen as being involved.

Based on the above considerations, the District has concluded that the proposed administrative changes do not constitute a "significant hazard", and that the health and safety of the public will not be endangered by the proposed additions to the Technical Specifications.

ATTAC K NT III DESCRIPTION OF PROPOSED CHANGES

, 1. Specification 4.11.1A., page 4-42: Moved item 1. into Specification 4.ll.1A, changing the air flow rate from 66,700 cpm 110% to 60,000 cfm 110% with clarification that the proposed value is applicable during conditions of containment integrity.

2. Specification 4.11.10.2(b), page 4-42b: Added in entirety.

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