ML20138G354

Safety Evaluation Supporting Amend 157 to License DPR-36

ML20138G354
Person / Time
Site:	Maine Yankee
Issue date:	05/02/1997
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20138G311	List: ML20138G308 ML20138G340 ML20138G354
References
NUDOCS 9705060269
Download: ML20138G354 (4)

Text

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5 j NUCLEAR REGULATORY COMMISSION l

WASHINGTON, D.C. 2006tM3001

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SAFETY EVALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0.157 TO FACILITY OPERATING LICENSE NO. DPR-36 )

MAINE YANKEE ATOMIC POWER COMPANY l

MAINE YANKEE ATOMIC POWER STATION I DOCKET N0. 50-309

1.0 INTRODUCTION

By letter dated February 7, 1997, the Maine Atomic Power Company (the licensee) submitted a request for changes to the Maine Yankee Atomic Power Station Technical Specifications (TSs). The requested changes would revise TS 3.12, " Station Service Power," to require both 115 kV power circuits to be operable when the reactor is critical and to limit or restrict the time during which Maine Yankee may continue to operate if one or both of the 115 kV power circuits become inoperable. These proposed changes place more restrictive operability requirements on the Maine Yankee offsite power system and provide increased assurance that power will remain available to the onsite distribution system while the reactor is critical.

The changes proposed by the licensoe are consistent with offsite power system requirements contained in NUREG-1432, " Standard Technical Specifications for Combustion Engineering Plants." NUREG-1432 documents the positions of the NRC on the Standard Technical Specifications for Combustion Engineering plants proposed by the Combustion Engineering Owners Group. 4 2.0 EVALVATION 2.1 Chanae 1 (TS 3.12.B.1)

Current TS 3.12.B.1 reads, "One ll5-kV incoming line in service." The licensee proposes to change this to "Both 115-kV incoming lines in service."

The offsite power system licensing basis for Maine Yankee is two redundant 115 kV incoming lines and a 345 kV line available within six hours. This proposed change is acceptable because it is consistent with the Maine Yankee licensing basis and it will result in increased assurance that power will be available to the onsite power distribution system while the reactor is critical.

9705060269 970502 PDR ADOCK 05000309 P PDR

2.2 Chanae 2 (Add New TS 3.12.8 Remedial Action No. 1)

The licensee proposes to add a new remedial action to account for the fact that TS 3.12.B.1 would now require two 115 kV incoming lines to be operable.

The new remedial action statement that the licensee proposes to add would read, "If one 115-kV incoming line becomes inoperable, restore it to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />." This new remedial action would be numbered as Remedial Action No. 1.

The Maine Yankee offsite power system is designed to have redundant 115 kV incoming lines available to immediately power the onsite power distribution system in the event of a reactor trip. If one 115 kV incoming power line becomes inoperable while the reactor is critical, the other 115 kV incoming line is still available. Because one incoming power line is still immediately available to power the onsite power distribution system, it is appropriate to allow the plant to continue to operate while the licensee works to restore the inoperable line. Licensees are allowed to continue operating for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> while working to restore an inoperable redundant source nf offsite power. This proposed change is acceptable.

2.3 Chanae 3 (Revise Old TS 3.12.B Remedial Action No.1)

Current TS 3.12.B Remedial Action No. I reads, "If the 115-kV incoming line becomes unavailable, the NRC shall be notified within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the plans i for restoration of service and the line must be restored to the available i status within seven days." The licensee proposes to change this to "If both 115-kV incoming lines become inoperable, restore one to operable status within i 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />." The license also proposes to renumber this remedial action l statement to Remedial Action No. 2.

i The licensee has proposed to make the requirement of this remedial action more i stringent by reducing the length of time that the plant may continue to l operate without a source of 115 kV power. Under the current version of this remedial action, the licensee must notify NRC within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of losing all 115 kV power, and the licensee is allowed seven days to restore at least one 115 kV incoming line. Under the proposed remedial action, the licensee will only have 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to restore at least one 115 kV incoming line. The 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of continued operation permitted under the proposed remedial action is allowed so that the licensee can restore a 115 kV incoming line or plan for an orderly shutdown of the reactor. This proposed change is in accordance with current NRC regulatory guidance and is acceptable.

2.4 Chanae 4 (Revise Old TS 3.12.B Remedial Action No. 2)

The licensee proposes to change the word " unavailable," which is used twice in the remedial action, to " inoperable." The licensee also proposes to renumber this remedial action to Remedial Action No. 3. '

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l This proposed change is editorial only, and it has been proposed so that the terms " operable" and " inoperable" would be uniformly applied in TS. The term

" operable" is defined in the TS definitions section. This proposed change is acceptable.

2.5 Chanae 5 (Revise Old TS 3.12.B Remedial Action No. 3)

The license proposes (a) to change "the 115-kV incoming line" to "one 115-kV '

incoming line," and (b) to change " restore the 115-kV line" to " restore the inoperable 115-kV line." The licensee also proposes to renumber the remedial action to Remedial Action No. 4.

The licensee has proposed to change "the 115-kV incoming line" to "one 115-kV incoming line" to reflect the fact that TS 3.12.B.1 would now require both 115-kV incoming lines to be operable when the reactor is critical instead of just one incoming line. This proposed change is a more stringent requirement and is acceptable for the reasons stated above. The licensee has proposed to add the term " inoperable" to clarify the remedial action and to uniformly apply the term in TS. This change is editorial only and is acceptable.

2.6 Chance 6 (Renumber Old TS 3.12.B Remedial Action No. 4)

The licensee pro;soes to renumber this remedial action to Remedial Action No. 5.

This change is editorial only and is acceptable.

2.7 Chanae 7 (Renumber Old TS 3.12.8 Remedial Action No. 5)

The licensee proposes to renumber this remedial action to Remedial Action No. 6.

This change is editorial only and is acceptable.

2.8 Chanae 8 (Basis)

The licensee proposes to change the word "available" to " operable" in the Basis Section and add new statements to the Basis Section which clarify that power operations may continue for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with one 115 kV incoming line inoperable and 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with both 115 kV incoming lines inoperable.

The changes to the Basis proposed by the licensee are acceptable.

The staff has evaluated the licensee's proposed changes documented above. In summary, the changes proposed by the licensee (1) will provide increased assurance that power will remain available to the onsite distribution system while the reactor is critical, (2) will ensure that offsite power will be restored with greater urgency if lost, and (3) will uniformly apply the usage of the term " operable" in TS, thereby clarifying TS. Each change proposed by the licensee in its February 7,1997, letter has been reviewed and found acceptable.

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3.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Maine State official was notified of the proposed issuance of the amendment. The State official had no comments.

4.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC 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 issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (62 FR 8799). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.

5.0 CONCLUSION

The Commission 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, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: V. Beaston Date: May 2, 1997 k