ML20213H115
| ML20213H115 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 11/12/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20213H110 | List: |
| References | |
| TAC-62789, NUDOCS 8611190101 | |
| Download: ML20213H115 (3) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 24 TO FACILITY OPERATING LICENSE NO. NPF-29 MISSISSIPPI POWER & LIGHT COMPANY MIDDLE SOUTH ENERGY, INC.
SOUTH MISSISSIPPI ELECTRIC POWER ASSOCIATION GRAND GULF NUCLEAR STATION. UNIT 1 DOCKET NO. 50-416
1.0 INTRODUCTION
By letter dated September 15, 1986, Mississippi Power & Light Company, (the licensee) requested an amendment to Facility Operating License No.
NPF-29 for the Grand Gulf Nuclear Station, Unit 1.
The proposed amendment would change the Technical Specifications by adding an inboard containment isolation check valve and two test connection valves in the post-accident sampling system (PASS) return line to Table 3.6.4-1, " Containment and Drywell Isolation Valves." These changes will be implemented prior to startup from the present refueling outage. The present containment isolation provisions for this line are a remote manual isolation valve in series with a pipe reducer (equivalent to a 1/4 inch orifice) which the t
licensee concluded meets the intent of Regulatory Guide 1.11. " Instrument Lines Penetrating Reactor Containment."
i 2.0 EVALUATION The NRC staff has reviewed the licensee's application and associated discussion and justification. The staff notes that the licensee had previously concluded that the present arrangement meets the intent of Regulatory Guide 1.11 because of the remote manual isolation valve in conjunction with the flow restriction provided by the 3/4 inch pipe to 3/8 inch tubing reducer. Regulatory Guide 1.11 provides an acceptable alternate basis for meeting the requirements of General Design Criterion 56 (GDC 56), " Primary Containment Isolation" in Appendix A to 10 CFR 50 for instrument lines connected to or penetrating primary reactor contain-ment (See NUREG 0800, Standard Review Plan (SRP), Section 6.2.4 "Contain-mentIsolationSystem"). The PASS is a system consisting of tubing, in-line instruments, valves and other components to obtain samples of reactor coolant after an accident.
It should not be considered, however, as an instrument line which must be open to perform its function. The multi-function PASS is normally isolated and is to be used only periodically following an accident. Therefore, Regulatory Guide 1.11 is not applicable to the PASS as an acceptable alternate basis for meeting GDC 56. The staff concludes that the present system is not an acceptable alternate basis 8611190101 861112 PDR ADOCK 05000416 P
. for meeting GDC 56. The staff notes that the plant is presently in a refueling outage during which primary containment isolation is not required and that the proposed additional isolation valves will be installed prior to startup from the outage.
The licensee proposes to install an inboard isolation check valve in the PASS return line which enters containment through penetration 718. Con-tainment isolation would then consist of two valves in series both of which are outside the containment - the new check valve and the present remote manual valve. The remote manual valve is normally closed and controlled remotely by a key locked handswitch in the control room.
Since the two valves are tied into a residual heat removal (RHR) relief valve discharge line which penetrates containment and terminates in the suppression pool, an isolation valve located inside containment could block flow in this discharge line preventing the relief function. The proposed addition of an inboard isolation check valve outside containment in series with the existing locked closed remote manual valve provides double valve protection from containment leakage during primary containment isolation.
Because placing an isolation valve inside containment for Penetration 71B is not practical, the proposed two valves outside containment are an acceptable alternate basis for meeting GDC 56 as identified in SRP Section 6.2.4, Paragraph II.6.d.
The licensee also proposes to add two test connection valves to penetration 71B to provide leak testing capability. These manual isolation valves will be closed, except during leakage testing, and they are, therefore, acceptable.
These modifications to the PASS require changes to Grand Gulf Unit 1 Technical Specifications Table 3.6.4 1, " Containment and Drywell Isolation Valves." The proposed additions to Table 3.6.4-1 of the three new valves will make them subject to the limiting conditions for operation and appli-cable surveillance requirements of Technical Specification 3/4.6.4.
The proposed modifications are, 'therefore, acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves changes to requirements with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes to the surveillance requirements. 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 signifi-cant increas,e in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that this amendment i
involves no significant hazards consideration and there has been no public coment on such finding. Accordingly, this amendment meets the eligibility criteria for cateoorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to10CFR51.22(b),noenvironmentalimpactstatementorenvironmental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
The Commission made a proposed determination that the amendment involves no significant hazards consideration which was published in the Federal Register (51 FR 36098) o, October 8, 1986, and consulted with the state of Mississippi.
No public coments were received, and the state of Mississippi did not have any comments.
The staff has 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 Comission's regulations and the issuance of this amendment will not be inimical to the common defense and the security nor to the health and safety of the public.
Prinicipal Contributors:
F. Witt, Plant Systems Branch, DBL L. Kintner, BWR Project Directorate No. 4 DBL Dated:
November 12, 1986