ML20210Q919

Safety Evaluation Supporting Amend 98 to License NPF-47

ML20210Q919
Person / Time
Site:	River Bend
Issue date:	08/26/1997
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20210Q918	List: ML20210Q912 ML20210Q919
References
NUDOCS 9709020207
Download: ML20210Q919 (8)

Text

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NUCLEAR REGULATORY COMMISSION WASHINGTON. D.C. See4 Hoot u..+

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 98 10 FACILITY OPERATING LICENSE NO. NPF-47 ENTERGY OPERATIONS. INC.

RIVER BEND STATION. UNIT 1 DOCKET NO. 50-458

1.0 INTRODUCTION

By application dated November 6,1996, Entergy Operations, Inc. (the licensee) requested changes to the Technical Specifications (Appendix A to Facility Operating License No. NPF-47) for the River Bend Station, Unit 1.

The proposed changes would revise the Technical Specifications (TSs) to permit an increase in the allowable leak rate for the main steam isolation valves (MSIVs) and deleted both the. Main Steam-Positive Leakage Control System (MS-PLCS) and the Penetration Valve Leakage Control System (PVLCS),

By letter dated July 31, 1997, the licensee provided additional clarification for the deletion for the PVLCS and requested the deferral of review for increasing the HSIV leakage rate and the deletion of the MS-PLCS. This Safety Evaluation therefore addresses only the request to delete PVLCS.

The licensee's July 31, 1997, letter did not change the staff's conclusions in the initial no significant hazards consideration determination.

2.0 flACKGROUND j

The PVLCS consists of two independent, manually initiated subsystems, either of which is capable of preventing fission product leakage from the containment following a Loss-of-Coolant-Accident (LOCA).

Each subsystem is comprised of an air compressor, an accumulator, an injection valve, and three injection headers with separate isolation valves. This system has additional headers, which allows the PVLCS air compressors to serve as a supply to the MS-PLCS and a backup supply to the safety relief valve (SRV) actuator air accumulators.

The PVLCS lines to the containment isolation valves will be cut and capped and the remainder of the system left in service for MS-PLCS and for SRV actuation.

The containment isolation valves served by the PVLCS will continue to be tested as containment isolation valves by the local leak rate (Type C) test requirements in accordance with the Primary Containment Leakage Rate Testing Program.

3.0 EVALUATION The PVLCS was designed and was. intended to limit the leakage past certain containment isolation valves following an accident by pressurizing the space between the discs of the isolation valves. The system has proven to be costly to maintain and test and the licensee proposes to delete the requirement for 9709020207 970826 PDR ADOCK 05000458 P

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1 the system based on the dose assessment of not having the system to limit leakage. The isolation valves will continue to be type C tested on the same frequency but the PVLCS will no longer contribute to containment it.-leakage and possible overpressurization of containment following an accident. Our evaluation of the proposed deletion of PVLCS examines the dose assessme t assuming some leakage past the isolation valve will occur and the system modifications will limit in-leakage to the containment.

Evaluation of the deletion of MS-PLCS and an increase in the leakage rate of the main steam isolation valves is deferred.

Dose Assestmmi The staff has reviewed the licensee's analysis and finds that their offsite and control room operator radiological consequence assessments met the relevant dose acceptance criteria.

Furthermore, the staff finds that the licensee's calculational methods used for the offsite and control room o)erator radiological consequence assessments are also acceptable.

To verify tie licensee's assessments, the staff has performed independent assessments of the offsite and control room operator radiological consequences resulting from a postulated LOCA without the PVLCS. In its assessments, the staff considered the following three fission product transport paths to the environment following a postulated LOCA:

(1) containment leakage (2) PVLCS leakage s

(3) post-LOCA leakage from engineered safety features (ESF) outside containment m

The calculated offsite doses resulting from a postulated LOCA and the parameters and assumptions used in recalculation are given in Tables 1 and 2 of this safety evaluation, respectively.

The staff finds that the recalculated offsite doses meets the dose guidelines set forth in 10 CFR Part 100. The calculated control room operator doses following a postulated LOCA, along with the parameters and assumptions used, are listed in Table 3 of this safety evaluation. The staff also finds that the calculated whole-body and equivalent organ doses (thyroid) are within the guidelines of SRP Section 6.4 and therefore, within the acceptance criteria specified in GDC 19 of Appendix A to 10 CFR Part 50.

Based on the above evaluation and the calculated radiological consequences shown in Tables 1 and 3, the staff concludes that the proposed deletion of the PVLCS is acceptable. The staff further concludes that the existing distances to the exclusion area and to the low population zone boundaries of the River Bend Station, in conjunction with the engineered safety features provided in the River Bend Station, Unit 1, are still sufficient to provide reasonable assurance that the radiological consequences of a postulated LOCA will be within the dose guidelines set isrth in 10 CFR Part 100 and the control room operator dose acceptance criteria specified in GDC-19 of Appendix A to 10 CFR Part 50. This conclusion is based on the staff review of the applicant's analysis and on the independent analysis by the staff which confirms that the calculated doses are within these guidelines.

. System Modifications / Technical Specifications The PVLCS air compressors and accumulator tanks provide air to the MS-PLCS and serve as long term safety-related backup air supply to the SRV and ADS accumulators.

This part of the system will remain and will continue to be referred to as PVLCS components in the MS-PLCS technical specifications. This will minimize the necessary changes to procedures and operating instructions until the removal of the MS-PLCS system may be justified by the licensee and approved by a future license amendment. The deletion of the PVLCS technical specification is acceptable.

Operation of the PVLCS on the containment isolation valves also introduced the possibility of air leakage into and overpressurization of the containment.

The Primary Containment Isolation Valve technical specifications contain a requirement to limit the in-leakage from both the PVLCS and MS-PLCS to prevent overpressurization and surveillance requirements to test the combinations of MS-PLCS and PVLCS valves at their system pressures. With removal of the PVLCS, the isolation valves served by PVLCS will no longer be subjected to PVLCS air in-leakage in the long term following an accident, therefore, the Primary Containment Isolation Valve technical specification is being modified to delete the PVLCS tests. This is acceptable.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Louisiana State Official was notified of the proposed issuance of the amendment. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changos a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is 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 (62 FR 125). 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 prepared in connection with the issuance of the amendment.

6.0 CONCLUSION

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

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activities will be conducted in compliance with the Comission's regulations, and (3) the issuance of the amendment will not be inimical to the comon defense and security or to the health and safety of the public.

Principal Contributors: Jay Lee J. Puls.ipher D. Wigginton Date: August 26, 1997

1 hs TABLE 1 i

Radiological Consequences of Loss-of-Coolant' Accident (rea)

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EAB LPZ Thyroid Whole Body Thyroid

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i Table 2 Assumptions Used to Calculate Offsite Radiological Consequences Resulting from Loss-of-Coolant Accident Parameter yalug Power level 3039 MWt Fraction of core inventory released Noble gases 100%

Iodine 50%

Iodine initial plate-out fraction 50%

Iodine chemical species Elemental 91%

Particulate 5%

Organic 4%

3 Suppression pool water volume 1.24E+5 ft Suppression pool decontamination factor (effective)

Noble gas 1

Organic iodine 1

Elemental iodine 7.87 Particulate 7.87 Drywell Leakage (suppression pool bypass) 3%

Iodine dose conversion factors ICRP-30 PVLCS leak rate 1.7E+5 cc/hr Iodine partition factor for ECCS leak 10 ECCS leak rate 1 gpm Standby gas treatment system Filter efficiency 99%

3 Flow rate 2500 ft / min Secondary containment filtration Filter efficiency 99%

3 Flow rate 2E+4 ft / min Drawdown time 213 seconds 9.5E+5ft}3 1.43E+6 f Primary containment and drywell: free volume Secondary containment free volume Secondary containment mixing efficiency 50 percent 3

Annulus Building free volume 1.79E+5 ft Breathing rates Regulatory Guide 1.3

o Table 2(continued)

Assumptions Used to Calculate Offsite Radiological Consequences Resulting from Loss-of-Coolant Accident 3

Atmospheric Dispersion Factors (x/Q) (seconds /m )

O to 2 hr EA8 9.01E 0 to 8 hr LPZ l.14E-4 8 to 24 hr LPZ 8.00E-5 1 to.4 day LPZ 3.71E-5 4 to 30 day LPZ l.23E-5 1

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TABLE 3 Assumptions and Estimates of the Radiological Consequences to Control Room Operators following a LOCA 3

Control room free volume 2.41E45 ft Recirculation Rates 1957 CFM Filtered Intake 1947 CFM j

Unfiltered Intake 0

Filtered Recirculation

?957 CFM filter Efficacy 99%

Unfiltered control room i

infiltration rate 10 CFM Duration of accident 30 days t

Breathing rate of operators in control room for the 3

course of the accident 3.47E-4 m /sec Control room y/Q 3

0 - 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 4.04E-3 sec/m3 8 - 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 3.03E-3 sec/m 3

24 - 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> 9.29E-4 sec/ms 96 - 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> 1.62E-5 sec/m lodine Dose Conversion factors ICRP-30 Control Room Operator Occupational factors 0 - 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 1

24 - 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> 0.6 96 - 720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br /> 0.4 Doses to control room operators (rem)

Thyroid Whole Body 3.4 2.4

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