ML17319A604
| ML17319A604 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 08/29/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17319A603 | List: |
| References | |
| NUDOCS 8009240089 | |
| Download: ML17319A604 (4) | |
Text
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Op**4 UNITEDSTATES NUCLEAR REGULATORY COMMISSION WAhHINdTON, D. C. 20666 SAFETY EVALUATION AND ENVIRONME TAL IMPACT APPRAISAL BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 40 TO FACILITY OPERATING LICENSE NO.
DPR-58 AND AMENDMENT NO.
23 TO FACILITY OPERATING LICENSE NO.
DPR-74 INDIANA AND MICHIGAN ELECTRIC COMPANY DONALD C.
COOK NUCLEAR PLANT UNIT NOS.
1 AND 2 DOCKET NOS. 50-315 AND 50-316 INTRODUCTION By letter dated April 6, 1979, as supplemeted on September 13, 1979, the Indiana and Michigan Electric Company (the licensee) proposed two environmental related changes for the D. C.
Cook Nuclear Plant.
One proposal was to extend a thermal plume study period beyond the allowed time window (April 15 to May 15) on into June.
The second proposal dealt with a modifica-tion of the Unit No.
1 discharge scour bed protection to correct a deficiency.
By letter dated November 2, 1979, the licensee proposed a revision to the Appendix A Technical Specifications for Unit No.
1 to increase the minimum water temperature of the refueling water storage tank (RWST) to 70'F to be consistent with the Unit No.
1 reload safety analysis performed by Exxon.
By letter dated April 3, 1980 the licensee provided a
summary report of the thermal plume monitoring effort completed to date, a comparison of the measurements with model predictions and a justification for not requiring any further measurements.
In addition a copy of the facility's NPDES Permit
( No. MI0005827) was attached Some modifications to the licensee's proposals were necessary to meet our requirements.
These modifications were discussed with and agreed to by the licensee.
DISCUSSION AND EVALUATION SAFETY RELATED PROPOSAL 1.
Refuelin Water Stora e Tank 0 eratin Tem erature - Unit No.
1 In its letter dated November 2, 1979, the licensee proposed seven changes to the Technical Specifications of their Unit Nos.
1 and 2 licenses.
Proposed change number six which is the only one being dealt with in this evaluation, would increase the RWST operating temperature on Unit No.
1 from 35'F to 70'F.
The original minimum temperature limit of 35'F was to prevent freezing in the tank and related liners, however, 8009840 089 during the Unit No.
1 Reload Safety Analysis performed by Exxon Nuclear
- Company, the minimum safety injection water was assumed to be 70'F.
The-RWST water temperature also determines the initial spray water temperature delivered to the containment following a loss of coolant accident (LOCA) ~
Spray water temperature is one of the factors in the emergency core cooling system analysis which determines the containment back-pressure following a
LOCA.
We agree that the minimum RWST temperature should be increased
- to 70'F to be
- consistent with the completed analyses.
The changes to the Technical Specification as proposed by the licensee, are acceptable.
Likewise, Limiting Condition for Operation (LCO) 3.1.2.8,.b.3 and Surveillance Requirement 3.1.2.8.b.3 of the Unit No.
1 Appendix A Technical Specifications should be changed to show a minimum temperature of 70'F for the RWST solution temperature.
A similar correction is not required for the Unit No.
2 Technical Specifications which already appropriately show the minimum allowable RWST temperature to be 80'F which is consistent with the LOCA analysis for Unit No. 2.
ENVIRONMENTALLY RELATED PROPOSALS 2.
Thermal Plume Measurements of Water Dischar e - Unit Nos.
1 and 2
We initially requested that the licensee validate the predictive model used to assess the impacts of the thermal discharge from the plant. 'he test requirements were covered in the Envi'ronmental Technical Specifica-tion ETS 4.1.1.2.
The validation was to be accomplished by comparing the model predictions to four actual plumes measured during fall, winter, spring and summer.
The plumes were measured during summer and fall of 1978.
The winter measurement was missed due to dangerous ice conditions and, that spring, the plant was at low power due to refueling.
The latter condition precluded meaningful measurements.
The licensee proposed in its April 6,
1979 letter a delay of the spring monitoring until later in the year; essentially proposing a second summer measurement.
The staff considered this to be an unacceptable substitution noting the dissimilarity between spring and summer lake conditions.
With regard to the missing winter measurements, the licensee advised the staff that winter conditions at'the site created hazardous conditions, on the lake.
They doubted that a data set could be collected without endangering the boat crew.
We have considered the conditions described and concur that whatever value might accrue from the data is offset by the potential for injury or loss of life.
Subsequently, the licensee submitted a model validation study which utilizes all available operational data.
The licensee compared pre-dicted and actual plumes and concluded that the model has been adequately validated and supports the environmental impact assessments which relied on the model prediction.
We reviewed the report and have not identified any significant discrepancies.
In addition, the State permits for plant operation, based in part or the assessment of therma'l
- impact, have already been issued.
Thus, while we note that the licensee has not met the letter of the initial environ-mental T.S. with regard to thermal monitoring, we now consider the additional monitor ing unnecessary.
We, therefor e, concur with the licensees'equest that the monitoring requirement be deleted from the Technical Speci fications.
3.
Modifications to the dischar e scour bed rotection for Unit 1
By letter dated April 6, 1979 and as supplemented by letter dated September 13, 1979, the licensee has proposed a modification to the Unit No.
1 discharge structure scour bed to alleviate a scouring problem in the area immediately in front of the discharge jets.
This area was originally constructed with a riprap bed.
However, the high velocity discharge, especially during times of heavy surface
- waves, eroded a
position of the scour bed and created a hole in the grout apron.
The licensee attempted to correct the problem by replacing the riprap in the scoured out area.
It was again scoured out.
The licensee
- proposes, as a permanent solution to the problem, to replace the eroded portion of the riprap scour bed with a concrete
- one, poured in place under water.
The licensee has agreed to periodically inspect this scour bed and report its findings to the NRC.
We have reviewed the design bases and find the proposed plan acceptable.
ETS Section 4.1.1.4 should be appropriately revised to ref'lect the fact that the scour bed is now more than of riprap construction and to accommodate the need for further studies in the event major modifications are made as proposed by the licensee.
The licensee has agreed to such revisions of ETS Section 4.1.1.4.
4 In reaching our conclusion that the proposed modification is acceptable, we also considered whether operating with the modified scour bed protections would alter the conclusions made in our earlier environmental evaluations on this plant.
These considerations are presented below.
In the August 1973 Final Environmental Statement (FES) fol D. C.
Cook Units 1
and 2, we discussed the potential for scouring the lake bottom from the high velocity offshore discharge (Section III.D.l.b(4), page III-22).
The FES recognized that placement of the scour bed around the'ischarge-jets would displace or eliminate those benthic organisms occupying the area of the scour bed (Section Y.C.2.c(l), page V-22).
Serious bottom scouring was not expected to occur in the immediate discharge
- area, thus direct effects of sediment scour, long-term increase in turbidity, and damage to benthic organisms were all expected to be minimal.
The recent changes to the scour bed resulting from station discharges have occurred in the area where previous displacement of benthic organisms
- occurred, thus no significant impact to benthics in that, area should result.
A permanent solution to the scour problem is warranted to maintain the minimum conditions o'f turbidity and associated effects, to biota evaluated in the FES.
The placement of concrete in the immediate scour'bed should ensure that long term effects are kept to a minimum level.
The proposed changes and any. resulting effects therefore appear to fall within the range of effects previously reviewed and found to be acceptable in the FES.
'\\
Environmental Consideration We have determined that the amendments do not authorize a change in effluent types or total amounts nor an increase in power 1eve1 and will not result in any significant environmental impact.
Having made this determi nation, we have further concluded that the amendments involve an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR $51.5(d)(4), that an environmental impact statement or negative declaration and environ-mental impact appraisal need not be prepared in connection with the issuance of these amendments-Conc1usion We have concluded, based on the considerations discussed above, that:
(1) because the ainendments do not involve a significant increase in the probability or consequences of accidents previously considered and do not involve a significan) decrease in a safety margin, the amendments do not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public wi 11 not be endangered by operation in the proposed
- manner, and (3) such activities wi 11 be conducted in compliance with=the Coranission's regulations and the issuance of these amendments will not be inimical to the common defense and s'ecurity or to:the health and safety'f the puh1ic-Date:
August 29, 1980