ML19316B188
| ML19316B188 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 05/27/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19316B182 | List: |
| References | |
| NUDOCS 8006120026 | |
| Download: ML19316B188 (3) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 48 TO FACILITY OPERATING LICENSE NO. DPR-40 OMAHA PUBLIC POWER DISTRICT FORT CALHOUN STATION, UNIT NO. 1 DOCKET NO. 50-285 Introduction In response to the NRC's July 23, 1979 letter to Omaha Public Power District (OPPD) concerning secondary water chemistry, OPPD submitted a request to incorporate a license condition on September 20, 1979. OPPD has also requested, by letters dated March 8 and October 24, 1978, minor administrative changes to the shock suppressor (snubbers) requirements.
Discussion and Evaluation Secondary Wa ar Chemistry - Addition of a Licensing Condition The NRC staff recognizes that different utilities use different secondary water treatment methods to limit steam generator tube corrosion. Moreover, we recognize that a licensee's choice of a particular water treatment method, including specific values of operating limits for chemistry parameters, is governed by plant and site characteristics that are unique to each facility.
In addition, we do not believe at this time that sufficient service experier.ca exists to conclude that any particular method is superior to another for controlling impurities that may be introduced into the secondary coolant.
Such experience would be necessary before prescriptive Technical Specifica-tions on secondary water chemistry could, with assurance, minimize tube degradation.
Restricting the amount of chemical additions to control the water chemistry parameters would not ensure the desired steam generator operating conditions.
Realizing that meeting the secondary coolant water quality crits-i would not be possible during all periods of operation, it is necessary that the most effective procedure Tor reestablishing out-of-specification chemistry parameters be available without unduly restricting plant operations. This can be
. accomplished most rapidly by continuing to operate the unit so that chemical additives to the secondary water can be made to achieve a balanced chemistry.
In particular, we have concluded that Technical Specifications on secondary water chemistry would not provide adequate flexibility to allow desired water conditions to be achieved gradually or ensure long-tenn tube integrity.
In addition, these specifications may not limit specific types of severe tube degradation, particularly "denti ng".
Furthennore, the possible adverse effects of any secondary water parameter limits on the steam purity that could lead to potential failure of rotating turbine components must also be considered before specific limits are required.
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Fort Calhoun 1 We believe that other methods for reducing the impurity concentration in the steam generator such as periodic chemical cleaning for long-term solution, fluxing or free surface boiling for an intermediate term solution, or the use of cheiating agents for the control of secondary water purity are more practical.
These methods are likely to be more effective in limiting corro-sion than specific Technical Specifications that may lack the flexibility needed for proper control of secondary water chemistry. The NSSS vendors are now considering these alternate methods in lieu of restrictive secondary water chemistry limits for assuring steam generator tube integrity. We proposed that the licensee implement a secondary water chemistry monitoring program to, inhibit steam generator tube degradation.
By letter dated September 20, 1979, the licensee agreed to the program and applied for a license amendment to so
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condition the license.
In addition, other existing Technical Specification limiting conditions for operation and surveillance requirements for secondary water monitoring require-mento provide assurance that steam generator tube integrity will not be reduced below an acceptable level for adequate margins of safety.
These specifications are.
1.
Technical Specification 2.1.3(1)c. - Secondary Water Activity.
2.
Technical Specification 2.1.4(3) - Primary to Secondary Leakage Rates.
3.
Technical Specification 3.3.(2) - Steam Generator Tube Surveillance and Plugging Criterion.
Based on the above and since OPPD's submittal, dated September 20,1979, is in accordance with our request, we find the proposed License Condition to be acceptable.
Shock Suppressor Changes On March 8,1978, OPPD submitted a request to add two snubbers to Table 2-6 of the Technical Specifications. This request is in accordance with the provisions of Specification 2,18 which allows additions of safety related snubbers without prior licensing amendments. Since this is an administrative matter involving updating of the snubber listing, the staff finds this request to be acceptable.
Gr. October 24, 1978, OPPD submitted a request to revise Specification 2.18 to allow testing of accessible hydraulic snubbers during reactor operation subject to various restraints. The staff has reviewed this request and has made the following conclusion.
The existing requirements of Specification 2.18 allow any snubber to be inoperable for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, which provides adequate time to repair or replace many of the snubbers should one be found to be inoperable, while limiting the time for inopera-bility to provide assurance of protection for low probability events. The proposed change would allow any one snubber to be removed from service for up to two hours
Fort Calhoun 1 for testing provided no other snubber listed in Table 2-6 is known to be inoperable and no other snubber is being tested. Since 1) only one snubber (out of more than 300) will be inoperat;e at any time, 2) the time that the snubber is inoperable is limited to two hours, and 3) more in-depth testing can be accomplished during operation when maintenance activities are not as numerous as they are during a shutdown period, the staff finds this proposed change to be acceptable.
Environmental Consideration We have determined that the amendment does not authorize a change in effluent types'or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 551.5(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 this amendment.
Conclusion We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Dated:
May 27, 1980 1
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