ML19250C478
| ML19250C478 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 11/02/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19250C477 | List: |
| References | |
| NUDOCS 7911260266 | |
| Download: ML19250C478 (3) | |
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ENVIRONMENTAL IMPACT APPRAISAL BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 40 TC FACILITY OPERATING LICENSE NO. OPR-42 AND AMENDMENT NO. 34 TO FACILITY OPERATING LICENSE NO. DPR-60 NORTHERN STATES POWER COMPANY PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-282 AND 50-306 Introduction By letter dated October 30, 1979, the Northern States Power Company (the licensee) requested an amendment to Facility Operating License Nos. DPR-42 and DPR-60 for the Prairie Island Nuclear Generating Plant, Unit Nos.1 and 2.
This amendment would change the Technical Specifications, Appendix B to the licenses, to permit a special chlorination program for the circulating water system to destroy the parasitic amoeba which have been discovered in this system.
During our review of the licensee proposals for these amendments, we found that certain changes were necessary to meet our requirements.
The licensee staff agreed to these changes and they have been incorporated in these amend-ments.
Discussion The licensee proposes to conduct a special chlorination program (up to twice a year) to destroy Naeglaria fowleri, a parasitic protozoan that causes primary amoebic meningoencephalitis. Although the Minnesota Department of Health does not consider the existence of the amoeba to present a public health threat, the presence of the organism in the cooling towers and circulating water system does present an occupational health concern. As a precaution, plant personnel have been instructed to wear rubber gloves when touching plant circulating water and wear respirators when working in the area of the cooling towers.
Literature references and recommendations by Dr. Richard Tyndall of the University of Tennessee indicate that exposure to chlorine at a concentration of 2 ng/l (measured as free chlorine) for a period of six hours should be effective to destroy both the amoeba and its encycsted form.
Use of chlorine for a period of six hours necessitates a change to the ETS, as the present chlorine specification limits the total time of chlorination to two hours each day.
The treatment plan proposed by the licensee and which has been reviewed and approved by the Minnesota Pollution Control Agency (MPCA) will consist of two phases:
3 0 076 291128o 2G6
. Phase 1 will occur during helper cycle operation and will be limited to chlorination of the cooling towers with subsequent dechlorination I.
to less than the lower limit of detection (<0.05 mg/1) with sodium This treatment is designed to prevent sulfite prior to discharge.
large amounts of biological material removed from the cooling towers Since it is impossible to from entering the plant intake systems.
predict the amount of material the dechlorination will remove, the It is length of time for Phase 1 cannot be stated in advance.
anticipated that three to four hours should be sufficient.
Phase 2 will occur during closed cycle operation with chlorination of the circulating water system for six hours at 2 mg/l free chlorine.
II.
Dechlorination will again be effected with sodium sulfite as it was in Phase 1.
Evaluation To aid in the effectiveness of the chlorination treatment, a biodispersant, Nalco 7348 (which presently is being used in the cooling water system with the Chlorine con-approval of MPCA), will also be utilized during both phases.
centration in the circulating water system and discharge will also be extensively monitored during chlorination of both phases.
The transition from present (closed-cycle) operation to helper cycle to be used in Phase 1 requires a gradual reduction in recirculation canal temperature to For the months of prevent cold shock to fish residing in the discharge canal.
October through April, a SoF drop per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> i: allowed by the ETS. Thus, for the anticipated AT of about 150F, three days will be required to reach To prevent thermal shock, the same transition period helper cycle operation.
is required to bring the system back from helper cycle to closed cycle prior to initiation of Phase 2.
Thus, about three days will be required after Phase 1 before beginning Phase 2 treatment.
Because chlorine at concentrations of 2 mg/l are expected to be lethal to fish, attempts will be made to remove fish from the cooling water return canal prior to conmencement of operation. At present, the licensee plans to add copper Fish in the canal sulfate at a concentration of 0.3 mg/l as a fish dispersant.
are expected to sense the copper sulfate and actively seek areas free from the Thus, it is felt that the fish will leave the canal via the discharge The application of copper sulfate will be conducted by the licensee's chemical.
structure.
biologists in conjunction with Minnesota Department of Natural Resources Seining and electroshocking may be employed as well, in an attempt pe rsonnel.
to capture and reintroduce the fish outside the circulating water system.
In spite of these extensive efforts, there is still a potential for some fish mortality at the intake and in the circulating water system during this treat-In order to document such impacts that may occur, an impingement survey Additionally, any impacts associated with the chlorinated ment.
will be conducted.
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. cooling tower drift will be assessed. Also, after completion of the chlorination treatment program, samples will be take from the circulating water system to determine the effectiveness of the program eradicating Naegl_a_ria fowleri.
Based on the above discussion and evaluation, we conclude that no significant environmental impact is expected to occur from the chlorination treatment program to destroy the amoeba Naeglaria fowleri.
No temperature limits are expected to be violated and because sodium sulfite will be used to reduce free chlorine concentrations to below 0.05 ma/l prior to discharge, no chlorine concentration limits will be exceeded.
Therefore, we find the licensee's proposal to be acceptable for the first such chlorination pro gram. Any subsequent treatment may be modified according to the results of the first treatment.
Results of (1) the impingement monitoring conducted during the treatment program, (2) the assessment of chlorinated cooling tower drift, and (3) the chlorine monitoring data collected during the study should be provided by the licensee for NRC review.
The results of the samples for Naeglaria fowleri in the circulating water system should also be reported at the conclusion of the chlorination program.
Conclusion and Basis for Negative Declaration On the basis of the foregoing analysis, it is concluded that there will be no environmental impact attributable to the proposed actions other than has already been predicted and described in the Commission's FES for Prairie Island Nuclear Generating Plant, Unit Nos. i and 2.
Having made this conclusion, the Commission has further concluded that no environmental impact statement for the proposed action need be prepared and that a negative declaration to this effect is appropriate.
Date: November 2,1979 1390 078
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