ML20198H677

Discusses Plant Control Complex Habitability Envelope Justification for Continued Operation

ML20198H677
Person / Time
Site:	Crystal River
Issue date:	12/24/1997
From:	Raghavan L NRC (Affiliation Not Assigned)
To:	Richard Anderson FLORIDA POWER CORP.
References
TAC-M91823, NUDOCS 9801130365
Download: ML20198H677 (5)

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[*g A* *. UNITE] STATES s* } NUCLEAR REGULATORY COMMISSION

• WASHINGTON. D.C. 30866 4001 "s...../

December 24, 1997 Mr. Roy A. Anderson Senior Vice President Nuclear Operations Florida Power Corporation ATTN: Manager. Nuclear Licensing Crystal River Energy Complex (SA2A) 15760 W. Power Line Street Crystal River. Florida 34428-6708

SUBJECT:

CRYSTAL RIVER NUCLEAR GENERATING PLANT UNIT 3 - CONTROL COMPLEX HABITABILITY ENVELOPE JUSTIFICATION FOR CONTINUED OPERATION -

INTERIM ASSESSMENT RESULTS (TAC M91823)

Dear Mr. Anderson:

By letter dated December 15, 1997. you submitted a Justification for Continued Operation (JCO) for Crystal River Unit 3 (CR-3) related to tne Control Complex Habitability Envelo)e (CCHE). The U.S. Nuclear Regulatory Commission staff (NRC or the staff) 1as not completed its detailed review or confirmatory calculations of the data supporting the JCO. However, the staff has performed an initial assessment of the JC0 and its findings are summarized below.

As part of the CCHE Action Plan, you modified the Control Room Emergency Ventilation System (C. REVS), performed a tracer gas study of CCHE infiltration.

and re-analyzed CCHE accident doses. The measured unfiltered inlea' age exceeded the original design basis value. In the event of a design basis accident (DBA), this increase in Inieakage could result in CCHE doses exceeding the criteria of 10 CFR Part 50 Appendix A. General Design Criterion (GDC) 19. You re-calculated the CCHE doses using revised analysis assumptions and methodology. You identified this change in mcthodology as an unreviewed safety guestion (US0) and prepared the subject JC0 to demonstrate operability of the CCHE as provided in Generic Letter (GL) 91-18 Revision 1.

The staff has performed an initial review of the JCO. In its review, the staff also considered information provided in your letter of November 10. .

1997, and that presented during technical meetings conducted on November 14 and 20, 1997. Je are sharing this information with you so that you can take appropriate actions consistent with your restart plan. The staff's findings are as follows:

1. The staff recognizes your extensive effort in performing the tracer gas inleakage test and in the improvements made to the CREVS and to the CCHE envelope. The staff reviewed the test report and finds that the test methodology and its performance to be generally adequate. The staff finds reasonable assurance that the CCHE unfiltered inleakage would be limited to 462 cfm.

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2 Mr. Roy A. Anderson

2. You propose to substitute a mechanistic approach to address unfiltered inleakage for.the accepted deterministic approach described in analysis guidance such as regulatory guides and the Standard Review Plan (SRP).

In the accepted approach the measured inleakage rate is input to dose calculations as a constant value for the duration of-the event. You proposed using four inleakage rates ranging from 80 cfm for the period  !'

0 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> post-accident to 435 cfm at later periods. You developed a correlation between the measured inleakage rate and differential pressure across the CCHE boundary Your method assumes that the differential pressure is created by the force of wind on exterior CCHE surfaces. Using the four wind speeds used in determining atmospheric dispersion (X/0). you project four unfiltered.inleakage rates.

The staff recognizes the validity of wind induced structure pressure differentials. However, the staff finds that you have not provided sufficient justification for its assumption that the CCHE inleakage rate is only a function of wind speed. The CCHE has limited surfaces ex)osed to the wind. There are only a limited number of penetrations on t1ese exposed surfaces. The inleakage observed in the test was caused by pressure differentials created by the Auxiliary Building Ventilation System (ABVS), conditions that could occur during a DBA. Based on these considerations, the staff finds your proposed methodology does not provide an adequate basis for showing compliance with the GDC-19 criteria.

3. The JC0 describes analyses of a DBA Loss of Coolant Accident (LOCA) and a DBA Steam Generator Tube Rupture (SGTR). You stated that postulated doses from other DBAs would be enveloped _by the doses determined for these two events. By letter dated Der:'ber 9. 1997, the staff informad you that its analysis of a letdown line failure accident indicated that the CCHE thyroid dose could be as high as 39 rem. This dose exceeds the

-GDC-19 criteria. The staff finds that you have not demonstrated that the CCHE will be habitable for all DBAs.

4. The staff has reviewed the analysis assumptions and inputs summarized in the JC0 and in the November 10, 1997 letter. Several of your assumptions represent deviations from the design basis and from current

~ staff practice and regulatory guidance. The effect of the. contested assumptions would be an increase in postulated CCHE doses. The staff finds that an analyses incorporating these assumptions would not-provide an adequate basis for showing compliance with the GDC-19 criteria.-

5. On December 18. 1997. you informed the staff verbally, that you have identificti that the core inventory source terms used in your analyses had been found to be in error. While the expected magnitude of this deficiency may not be l_imiting, your analyses may need to be updated.

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-3 Mr. Roy A. Anderson On the basis of the above discussion, the staff has concluded that you have .

not adequately demonstrated that the radiation doses to control toom operators will be less than the criteria of GDC-19 during a DBA. Since.CR-3 has been

shutdowti for:an extended period, the radioactive inventory has decayed such that CCHE doses would.not likely exceed GDC 19 criteria for any design basis accident that would occur prior to initial criticality following restart. >

However, operation at mode 2 or higher does not appear to be justified on the basis of information provided to date. The staff may consider any interim compensatory measures that would provide a basis for a staff finding that the

. criteria of GDC-19 would be met.

We suggest that you schedule a meeting with us as soon as possible to discuss this matter. If you have any questions, please write or call me at (301) 415-1471.

Sincerely. -

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L. Raghavan, Project Manager

- Project Directorate 11-3 Division of Reactor Projects - I/II l

Office of Nuclear Reactor Regulation Docket No. 50-302 cc: See next page p

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Mr. Roy A. Anderson On the basis of the above discussion, the staff has concluded that you have not adequately demonstrated that the radiatien doses to control room operators will be less than the criteria of GDC-19 during a DBA. Since CR 3 has been shutdown for an extended period, the radioactive inventcry has decayed such that CCHE doses would nct likely exceed GDC 19 criteria for any design basis accident that would occur prior to initial criticality following restart.

However, operation at mode 2 or higher does not appear to be justified on the basis of information provided to date. The staff may consider any interim compensatory rieasures that would provide a basis for a staff finding that the criteria of GCC 19 would be met.

We suggest that you schedule a meetina as soon as possible to discuss this matter. If you have any questions, please write or call me at (301) 415-1471.

Sincerely.

/S/

L. Raghavan. Project Manager Project Directorate 11-3 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket No. 50 302 cc: See next page Dist ribution Docket File Public CR-3 Reading B. Boger J. Zwolinski OGC ACRS CMiller JHayes S.LaVei J.Jaudon Document Name: G.\ CRYSTAL \91823.ltr

• Bruce Boger for Hebdon, See previous concurrence. s To receive a copy of this document, Indicate in the box: "C" = Copy without attachmentlenclosure "E" =

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Mr. Roy A. Anderson CRYSTAL RIVER UNIT N0. 3 r Florida Power Corporation Cc: '

Mr. R. Alexander Glenn Corporate Counsel Mr. Robert E. Grazio, Director Florida Power Corporation Nuclear Regulatory Affairs (SA2A)

MAC-A5A Florida Power Corporation P.O. Box 14042 Crystal River Energy Complex St. Petersbu v Florida 33733-4042 15760 W. Power Line Street Crystal River, Florida 34428-6708 Mr. Charles G. Pardee, Director Senior Resident Inspector Nuclear Plant Operations (NA2C)

Florida Power Corporation Crystal River Unit 3 i Crystal River Energy Complex U.S. Nuclear Regulatory Commission 15760 W. Power Line Street 6745 N. Tallahassee Road Crystal River, Flerida 34428-6708 Crystal River, Florida 34428 Mr. Bruce J. Hickle. Director- Mr. John P. Cowan Director. Restart (NA20) Vice President, Nucient Production Florida Power Corporation (NA2E) '

Crystal River Energy Complex Florida Power Corporation 15760 W. Power Line Street Crystil River Energy Complex Crystal River, Florida 34428-6708 15760 W. Power Line Street Crystal River. Florida 34428-6708 Mr. Robert B. Borsum Framatome Technologies Inc. Mr. James S. Baumstark  !

1700 Rockville Pike, Suite 525 Director, Quality Programs (SA20)

Rockville, Maryland 20852 Florida Power Corporation Crystal River Energy Complex Mr. Bill Passetti 15760 W. Power Line Street Office of Radiation Control Crystal River, Florida 34428-6708 Department of Health and Rehabilitative Services Regional Administrator, Region II 1317 Winewood Blvd. U.S. Nuclear Regulatory Commission Tallahassee, Florida 32399-0700 61 Forsyth Street, SW., Suite 23T85 Atlanta, GA 30303-3415 Attorney General Department of Legal Af' airs Mr. Kerry Landis The Capitol U.S. Nuclear Regulatory Commission Tallahassee, Florida 32304 61 Forsyth Street, SW., Suite 23T85 Atlanta, GA 30303-3415 Mr. Joe Myers, Director Division of Emergency Preparedness Department of Community Affairs 2740 Centerview Drive '

Tallahassee, Florida 32399-2100 1

, Chairman l Board of County Commissioners l Citrus County 110 North Apopka Avenue

=lverness, Florida 34450-4245

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