ML20210C397
| ML20210C397 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 04/28/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20210C385 | List: |
| References | |
| TAC-61975, NUDOCS 8705060178 | |
| Download: ML20210C397 (2) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0.108 TO FACILITY OPERATING LICENSE NO. DPR-40 OMAHA PUBLIC POWER DISTRICT FORT CALHOUN STATION, UNIT NO. 1 DOCKET NO. 50-285
1.0 INTRODUCTION
By letter dated July 17, 1986 (Reference 1), Omaha Public Power District (OPPD) requested a change to the Technical Specifications for Fort Calhoun Station, Unit 1.
The change is in response to IE Bulletin 80-04 which
. required all PWR licensees to perform a review of Main Steam Line Break (MSLB) analysis for the station with continued feed water addition.
The staff review of OPPD's response to the guidelines of this IE bulletin identified no further action to be required of the licensee (Reference 2).
However, in Reference 1, the licensee has proposed a conservative logic for isolating the steam generators involving additional initiating signals.
The proposed changes also include some minor rewording of statements and nomenclature for clarity.
2.0 EVALUATION The Emergency Safety Feature Actuation System (ESFAS) includes isolation of steam generators during a design basis MSLB event. This involves closure of the Main Steam Isolation Valves (MSIVs) and their associated bypass valves along with the Main Feed Water Isolation Valves (MFWIVs) and their associated bypass valves.
As explained in Reference 2, the steam generator isolation for a Main Steam Line Break event at Fort Calhoun Station is accomplished by the following logic. A low steam generator pressure ini-f tiates the main steam isolation signal (MSIS), which closes the MSIVs. A high containment pressure initiates the Containment Isolation Actuation l
Signal (CIAS), which isolates the MFWIVs. With this logic, neither the high containment pressure signal nor the low steam generator pressure signal can individually initiate a complete isolation of the steam genera-tors.
It is desirable and conservative that each of the two diverse sig-nals should independently initiate the safety function of isolating the steam generators during a design basis MSLB accident.
OPPD has modified Fort Calhoun Engineered Safeguard Signal logic (FSAR Fig. 7.3-1), such that either high containment pressure or low steam gener-ator pressure will independently initiate the steam generator isolation O
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. signal which will close the main steam isolation and bypass valves and the main feedwater isolation and bypass valves.
This modification is more conservative than what has been previously approved by the staff and does not involve an unreviewed safety question.
The proposed changes to the Technical Specifications reflect this conservative design.
3.0
SUMMARY
The staff has reviewed the proposed changes to the Technical Specification and found them conservative and more explicit and, therefore, acceptable.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that the amendment involves no significant increase in the amounts, and no significant 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 Commission has previously published a proposed finding that the amendment involves no significant hazards consideration 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 $51.22(c)(9).
Pursuant to 10 CFR 651.22(b), no environme ?al impact statement or environ-mental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
We have concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations, and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
6.0 REFERENCES
1.
OPDD letter to NRC, H.R. Denton, dated July 17, 1986.
2.
NRC letter, R.A. Clark, to OPPD, W.C. Jones, dated July 22, 1982.
Date: April 28,1987 Principal Contributor:
I. Ahmed 4
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