ML20206J471
| ML20206J471 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 11/16/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20206J469 | List: |
| References | |
| NUDOCS 8811280214 | |
| Download: ML20206J471 (4) | |
Text
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3AFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 30 TO FACILITY OPERATING LICENSE NO. NPF-47 GULF STATES UTILITIES COMPANY RIVER BEND STATION, UNIT 1 DOCKET NO. 50-458 1.0 LNLRODUCTION By letter dated June 21, 1988, as supplemented October 31, 1988, Gulf States Utilities Company (GSU) (the licensee) requested an amendment to Facility Operating License No. NPF-47 for the River Berd Station, Unit 1.
The proposed amendment would inodify Technical Specification (TS) 6.8.4.d to (1) delete the requirement for NRC approval of the asiatic cl'am control program ( ACCP) prior to the introduction of river water to plant systems; and (2) delete the require-ment for monitoring to detect the presence of Corbicula in the Mississippi River and add the requirement for nonitoring to detect Cornicula in the clarifier influent.
In addition, by letter dated August 31, 1987 as rodified March 30, 1988 GSU proposed changes to its administrative procedure, ADM-0053, for the ACCP. The staff's approval of the changes to the ACCP are required per River Bend Station's Technical Spec.ification 6.8.4.d, Biofouling Prevention and Detection. This progran was implemented prior to introduction of river water to plant systems to prevent biofouling of safety-related equipmnt and was approved by the NRC's Septer.ber 27, 1985 letter. The significant proposed changes are in the area of biological inonitoring for asiatic clams, sampling and visual inspection, and chlorination and are based on the program experience. Other changes ere administrative or editorial in nature. The significant changes in ADM-0053 for ACCP are discussed below.
2.0 DISCUSSION AND EVALUATION 2.1 Biological Monitoring for Asiatic Clams (Section 6.2)
The licer.see has deleted the requirements for monitoring the presence or relative abundance of Corbicula in the Mississippi Ri/er channel. Monitoring for adult /large juvenile clams will continue in the embayment area where cir-culating water makeup is withdrawn. The licensee stated th6t the intent of the monitoring was to determine if there was a meaningful relationship between the method of sanpling arbient densities of young clams in the source water and the nethod of sanipling adult /large juvenile clams in the clarifier influent. The licensee indicated that several years of historical data exist for Corbicula in the river water near the site and the relationship of these two sampling lolia-tions has beer documented since the implementation of the ACCP. The licensee stated that of the two locations, data on young clar densities in the clarifier influent are more relevant than those of the river channel in determining the removal *fficiency of the clarifiers. Therefore, nonicoring of tre river channel
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.- sampling is no longer needed. Deletion of the river sampling near the site will not decrease the effectiveness of the ACCP as monitoring for clams will continue where circt:lating water makeup is withdrawn.
The licensee has elso deleted the requirement for increasing the sampling frequency of the clarifier effluent for larval / smaller juvenile clams in the event r.crmal servi:e water chlorination is interrupted for more than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.
The licensee stated that when the program was planned, it was expected that the clarifier would remove most of these planktonic clams.
Increasing the sampling frequency during chlorine lapses was supposed to provide evidence that the lack of biocide was inconsequential. The licensee stated that, based on the samp1-ing, it is now evident that the clarifier does not remove all these clams. To control these clams, the licensee is increasing the chlorination of the service watet system as discussed under the chlorination subsection in this SE.
Therefore, increasing the sampling frequency no longer serves a useful purpose.
2.2 Sampling and Visual Inspection (Section 6.3)
The licensee has deleted visual inspection of the auxiliary building unit coolers and replaced it with sampling until after refueling outage No. 2.
This is due to the welded design of the unit coolers which impedes access for direct visual inspection. The licensee stated that a fiberoptic technique is being tested for visual inspection and necessary modifications for probe access and isola-tion valve leakage are scheduled for work prior to operation after refueling outage No. 2.
The licensee will collect the sample of the sediment from the inlet coil drains and analyze it for evidence of clams and correlate tne results between the sample analyses and the visual inspections perfortred on the other safety-related heat exchangers. This sampling and monthly performance n.onitoring and trending required in the ACCP provides the redundant assurances tho' the auxiliary building unit coolers would not unexpectedly fail to serve their safety-related loads due to blockage by Corbicula_.
The licensee has also proposed pairing of the unit coolers (2 with 10, 3 with 4, 5 with 7, 6 with 9, and 11A with 11B) for sampling and visual inspection because of similar elevations, flow rates, heat loads, aaterials and configura-tion. Each renth one cooler from a pair will be sampled / visually inspected via the fiberoptic method such that each pair will be sampled / inspected at least twice per year. This is acceptable.
2.3 Chlorination (Section6.4)
The licensee proposed to increase the chlorination in the normal service water system to at least 0.6 ppm total residual chlorine (TRC) year round and to delete from the ACCP:
(a) the present provision that chlorination concentration can be reduced in the service water system from December thrcugh March and (b) the upper control limit of 0.8 ppm TRC. The above change for increase in chlorination will prevent the survival of larvae spawned within the circulating water system or entrained in the clarifier effluent, based on the ACCP experience.
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3 The licensee stated that when the ACCP was originally conceived, there was a concern that waste water discilarge permit limitation on chlorine in the cooling tower blowdown might not be met if a TRC concentration of 0.6 to 0.8 was used during winter months when evaporative dissipation in the cooling tower was low.
It was assemed that the spawning season for Corbicula in the source water occurs during the inonths of warmer river water temperature. The licensee stated that based on sampling, it is now evident that the above is not entirely true. The
'icensee has installed a system for injecting a dechlorinating chemical into ihe blowdown line so that the chlorine discharge permit limitation wil1 be met regardless of the ch'orine docage used. The proposed change will enhance the effectiveness of the ACCP, as use of biocide year round at a concentration of at least 0.6 ppm TRC will prevent survival of any larvae spawned within the circulating water system or the clarifier effluent.
The licenses's October 31, 1988 letter provided additional clarification regarding the addition of the dechlorinating chemical into the cooling tower blowdcwn. Arrnonium bisulfite is the reducing agent that is used by the licensee to react with the TRC. Approximately 5 parts per million of the bisulfite is maintained in the blowdown. The reaction between the TRC and the bisulfite produces mainly sulfate and chloride salts. The concentration of these salts from dechlorination represents a small percentage of these constituents in the blowdown and therefore does not significantly affect the composition of the blowdown.
In addition, the licensee stated that with regard to toxicity, the discharge of the antnonium bisulfite and reaction products are rot regulated by the Environmental Protection Agency, nor does the State of Louisiana specify water quality standards for dechlorinating agents and their reaction products.
2.4 StM1ARY Based on the above discussion and evaluation, the staff concludes that the proposed changes in the ACCP for river water sarpling and sampling frequency of the clarifier effluent (Section 6.2), for sampling and visual inspection of auxiliary building unit coolers (Section 6.3), and increase in chlorination (Section 6.4) are acceptable since the changes are supported by several years of data ond they will not decrease the effectiveness of the ACCP in providing early identification and preventing biofouling of scftsty related equipment.
With regard to the proposed TS changes, the staff concludes that the deletion of MRC staff approval of the ACCP prior to introduction of river water is acceptable because the staff approved the curre et ACCP by letter dated September 27, 1985. The staff also concludes ' ghat the deletion of inonitoring for Corbicula in the Mississippi River and adting the nonitoring requirertent for torbicu b in the clarifier inlet is acceptab'e based on the above discussion and evaluation.
3.0 ENVIRONMENTAL R SIDLRA, TION The amendment involves a change in the installation or use of a facility como0nent located within the restricted area as defined in 10 CFR Part 20.
ment involves no significant increase in The staff has determined that the arres the amounts, and no significant change in the types, of any effluents that nay
-4 be released offsite, and that there is no significant increase in individual er cumulative occupational radiation exposures. The Commission has previously issued a proposed finding that the amendment involves no significant hazards considerction and there has been no public comment on such finding. Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or envirorrental assessment need be prepared in connection with the issuance of the amendment.
4.0 CONCLUSION
The staff has concluded, based on the consitt:t 6tions discussed above, that:
(1) there is reasonable assurance that the health and safety of the will not be endangered by operation in the proposed manner, and (2) public such activities will be conducted in compliance with the Commission's regulations, and the issuance of. the arendment will not be inimical to the common defense and security or to the health and safety of the public.
Date:
November 16, 1988 Principal Contributors:
R. Goel and W. Paulson i
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