ML19325D431

Forwards Draft Safety Evaluation Supporting Proposed Tech Spec Amend to Modify Liquid Effluent Requirements,Per 891006 Telcon.Comments Requested

ML19325D431
Person / Time
Site:	Rancho Seco
Issue date:	10/19/1989
From:	Kalman G Office of Nuclear Reactor Regulation
To:	Bailey E CALIFORNIA, STATE OF
References
TAC-69016, NUDOCS 8910240054
Download: ML19325D431 (8)

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Docket No. 50 312 1<

l Mr. Edward Bailey Chief, Radiological Health Branch State Department of Health Services l

1232 Q Street.

Sacrasento, California 95814

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SUBJECT:

TRANSMITTAL OF DOCUMENT RELATED TO RANCHO SECO NUCLEAR GENERATING STATION (TACNO.69016) l~

Per our telecon on October 6,1909, a working copy of our safety l

L evaluation related to the proposed Rancho Seco Technical Specification l.

amendment to modify liquid effluent requirements is enclosed for your consnent. Please send comments to wy attention or telephone, 301 492 1367, if you would like to discuss this matter further.

Sincerely, 1

i orginal sign by George Kalman l

George Kalman, Senior Project Manager Project Directorate V 4

Division of Reactor Projects - !!!,

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October 19, 1989 i

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Docket No.

50 312 I

r Mr. Edward Bailey l

' Chief, Radiological Health Branch State Department of Health Services 1232 Q Street.

Sacramento, California 95814 l

SUBJECT:

TRANSMITTAL OF DOCUMENT RELATED TO RANCHO SECO NUCLEAR GENERATING STATION (TACNO.69016)

Per our telecon on October 6,1989, a working copy of our safety evaluation related to the proposed Rancho Seco Technical Specification amendment to modify liquid effluent iequirements is enclosed for your

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comment. Please send comments to my attention or telephone, 301 492-1367, if i

you would like to discuss this matter further.

Sincerely, 8

George Kalman, Senior Project Manager Project Directortte V Division of Reactor Projects - 111, i

IV, Y and Special Projects l

Office of Nuclear Reactor Regulation 4

Enclosure:

As stated cc: See next page i

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Mr. Edward Bailey Rancho Seco Nuclear Generating Station I

cc:

i Ns. Jan Schori General Manager Mr. John Bartus Sacramento Municipal Utility District Ms. JoAnne Scott 6201 S Street Federal Energy Regulatory Commission i

P.O. Box 15830 825 North Capitol Street, N. E.

Sacramento, California 95813 Washington, D.C.

20425

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Thomas A. Baxter, Esq.

Ms. Helen Hubbard l

Shaw, Pittman, Potts & Trowbridge P. O. Box 63 i

2300 N Street, N.W.

Sunol, California 94586 Washington, D.C.

20037 Environmental Conservation Mr. Steven Crunk Organization l

Manager, Nuclear Licensing Suite 320 Sacramento Municipal Utility District 101 First Street Rancho Seco Nuclear Generating Station Los Altos, California 94022 14440 Twin Cities Road Herald, California 95638-9799 l

Mr. Dan R. Keuter:

Mr. Robert B. Borsum, Licensing Assistant General Manager Nuclear i

Representative SacramentoMunicipalUti1ItyDistrict t

Babcock & Wilcox 14440 Twin Cities Road Nuclear Power Division Herald, California 95638-9799 1700 Rockville Pike. Suite 525 3

Rockville, Maryland 20852 l

Resident Inspector / Rancho Seco j

c/o V. 5. N. R. C.

t 14440 Tsiin Cities Road Herald, California 95638 i

i Regional Administrator, Region V U.$. Nuclear Regulatory Comission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596 i

i Mr. John Hickman senior Health Physicist i

Environmental Radioactive Management Unit l

Environmental Management Branch State Department of Health Services 714 P Street, Room 616 Sacramento, California 95814 I

r Sacramento County f

Board of Supervisors 700 H Street, Suite 2450 Sacramento, California 95814 (11) ww,-iww e

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SAFETY EVALUATION BY THE.0FFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDNENT NO.

TO FACILITY OPERATING LICENSE DPR-54 i

RANCN0 SEC0 NUCLEAR GENERATING STATION. UNIT 1 DOCKET NO. 50-312 I

1.0 INTRODUCTION

j By letters dated June 10, 1988 and January 11, 1989, the Sacramento Municipal Utility District (SMUD) proposed changes to the Technical Specifications (TS)fortheRanchoSecoNuclearGeneratingStation.

These changes consist primarily of refinements to radioactive effluent technical specifications (RETS) which had been approved on March 17, 1988 by Amendment No. 98 to Facility Operating License No. DPR-54 for Rancho Seco. Other proposed changes consist of administrative modifi-cations to maintain consistency in technical objective and format.

Amendment 98 had been issued to impose more stringent liquid effluent requirements on Rancho Seco to account for the ar'd environment in the vicinity.of the plant. The initial Rancho Seco RETS were based on Standard TS which were developed for the typical nuclear plant which l

discharges liquid effluents into a large body of water to dilute and disperse the radioactivity.

In the case of Rancho Seco, there is no large body of water to dilute plant discharges and the contribution'to the offsite dose from radioactivity released from Rancho Seco is more significant than from the typical plant.

Design objectives which govern offsite liquid releases are listed in 10 CFR 50. Appendix 1.

Due to Rancho Seco's atypical environment, the star.dard RETS are not an appropriate model to control offsite dose limits to meet the design objectives as specified in Appendix 1.

The RETS l

specify a lower,imit of detection (LLD) to be used during analysis for ly radioisotopes in discharge samnles. The inputs to the calculation for determining offsite dose include concentration of all the radionuclides l

(in excess of LLD) in the water being discharged. At a typical plant, L

the contribution to the offsite dose from any nuclide whose concentration l

is less than the LLD, as specified in the standard RETS, would be l

insignificant. However, at Rancho Seco, it is possible to exceed the offsite dose limits as specified by Appendix I while discharging water in concentrations less than the detection capability (LLD) required by the sttndard RETS.

Anendment 98 lowered the required LLD for Rancho Seco effluents to a level which would ensure that any contribution to the offsite dose which is significant to the Appendix I guidelines would be detected. The objective of the revised Rancho Seco LLD (Amendment 98) was to enable the DRAFT

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plant to compute c'fsite doses resulting from liquid effluents to 50% of Appendix I guidelines based on pre-release samp(post-release).les and to 10%

l guidelines based on monthly composite samples The :tancho i

Seco pre-release LLD's as specified by Amendment 98 are a factor of 25 1

less than the standard RETS requirements and post-release LLD's are a factor of 125 less than the stant'ard. The analysis techniques associated with these significantly lower LLD's are extremely demanding and challenge the state of the art for " field" analysis. Based on approximately one yecr of experience, the licensee determined that the LLD's, specified in Amendment 98, for several of the radioisotopes were not practical to achieve in the " field." The proposed amendment would increase the required LLD's for several isotopes commensurate with achievable field analysis techniques. The LLD's for several radioisotopes which are easier to detect in the " field" were lowered to compensate for the raised LLD's of radioisotopes which are more difficult to detect. The overall objective forcomputing50%.(pre-release)and10%(post-release)ofAppendixI criteria is not changed.

2.0 EVALUATION.

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Factitty Ops. rating License Amendment 98 listed the typical radioisotopes contained in nuclear power plant affluents and s>ecified a LLD to be used for each during analyses of effluent samples. Tie value of each LLD was computed to provide assurance that the concentration of every radioisotope contained in each batch of waste water which could provide a mathematically significant contribution to the offsite dose calculation was detected.

Radionuclide concentiJtions in each batch of waste water are used to determine the total radioactivity in that batch. The total radioactivity in each batch is converted, using the site specific offsite dose calcula-tion manual, to offsite dose. A running total of the dose contributions from each waste water batch is maintained to control cumulative offsite dose to 3 millirem per year (Appendix I design objective).

The licensee's operating experience indicates that it is not practical to i-analyze waste water samples from onsite collection tanks (batch collection tanks) using the LLD's currently specified for 5 of the 16 radioisotopes listed in the technical specifications and used as inputs to the offsite dose calculation. The 5 radioisotopes, their current LLD's and the new LLD's proposed by the licensee are listed below.

Isotope Current LLD Proposed LLD (uC1/cc)

(uCi/cc)

Mo-99 2E-8 6E-B Ce-144 2E-8 6E-8 Ba-140 2E-8 6E-8 l

Fe-59 4E-9 8E-9 Zn-65 4E-9 6E-9 DRAFT

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.The difference bet. ween the current LLD's and those proposed by the licensee equates to a quantity of radioisotopes released from the site which would be omitted from the dose computation of the annual offsite dose.

l To compensate for the quantity of radioactivity released from the site t

and omitted from the dose computation if the revised LLD's are adopted,l the licensee proposes to lower the currently specified LLD's for severa isotopes and thus maintain the overall objective of the liquid effluent program, i.e., incorporate a sampling program with sufficient sensitivity to control liquid effluents to within 50 and 10 percent of the Appendix I guidelines.

i The LLD's for 4 isotopes were decreased to compensate for the reduced sensitivity of the 5 isotopes which are difficult to detect. The 4 isotopes.

their current LLD's and the new LLD's proposed by the licensee are listed below:

Isotope Current LLD Proposad LLD (uCi/cc)

(uci/cc)

Sr-89 3E-8 SE-9 t

Sr-90 3E-8 1E-9 r

Cs-134 4E-9 3E-9 Cs-137 4E-9 3E-9 Six isotopes were removed from the monthly composite sampling list. The six isotopes are :

Mo-99 Cs-136 Ce-141 Ce-144 l

Ba-140 L

H-3 Although excluded from the post-release composite sampling requirements, the six isotopes are included in the post-release offsite dose calculation based on their measured pre-release concentration or LLD. This is a conservative change and, as such, will not decrease the licensee's ability to meet the Appendix I dose objectives.

The staff agrees that the changes proposed by the licensee do not alter the overall sensitivity for calculating the cumulative offsite dose resulting from radioactive liquid effluents. The isotopes whose LLD's the licensee proposes to increase are not the predominant isotopes associated with power reactor waste water and are not significant in terms of contribution to offsite dose.

If concentrations of these isotopes are in the LLD range, concentrations of the more predominant isotopes will be significantly higher. The overall impact on annual offsite dose from the less predominant I

l isotopes in their LLD range will not be mathematically significant.

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Based on our evaluation associated with proposed Amendment 98 that cor.-

cluded that the Rancho Seco RETS are adequate to regulate liquid effluents from the. plant to within 10 CFR 50, Appendix I guidelines and the evaluation of changes requested by this amendment, we conclude that changes to the LLD's as requested will not make a significant impact on the licensee's ability to regulate liquid effluents. Periodic monitoring of the offsite environment, as required by the technical s scifications, will verify the h

adequacy of the liquid effluent pregram at tancho Seco.

Specific changes associated with modifications to the LLD's involve the following sections of the revised technical specifications:

- Table 4.21-1,

- Specifications 4.21, t

-Table 4.26-1(LLDdefirdtion).

l Additionally, the following sections of the technical specifications were changed to maintain technical consistency and improve forinat:

- Table 4.21 (previous tables 4.21-1 and 4.21-2 were con 61ned)

- Surveillance requirements and bases of Specifications 4.21.1 and 4.21.2.

3.0 CONTACT WITH STATE OFFICIAL The NP.C staff has advised the State Department of Health Services, State of California.of the proposed determination of no significant hazards consideration. No comments were received.

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4.0 ENVIRONMENTAL CONSIDERATION

This amendment involves changes in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20, and in surveillance requirements. The staff has determined that the amendment involves no significant, increase in the amounts, and no signi-ficant 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 Cosnission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding.

Accordingly, this amendment meets the eligibility criteria for categorical exclusionsetforthin10CFR51.22(c)(9). Pursuantto10CFR51.22(b),

no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.

5.0 CONCLUSION

Wehaveconcluded,basedontheconsiderationsdiscussedabove,that(1) there is reasonable assurance that the health and safety of the public DRAFT

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l will not be endangered by oltration in the proposed manner, (2) such activities will be conducted in compliance with the Commission's -

i regulations,fense an)d security or to the health and safety of the public.

and(3 the issuance of the amendment will not be inimical to common de Principal' Contributor: George Kalman Dated:

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