ML20236L618
| ML20236L618 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 11/05/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20236L614 | List: |
| References | |
| NUDOCS 8711100468 | |
| Download: ML20236L618 (4) | |
Text
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UNITED STATES.
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.E NUCLEAR REGULATORY COMMISSION n
E WASHINGTON, D. C. 20555
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H SAFETY EVALUATION BY THE OFFICE OF NUCLEAR-REACTOR REGULATION RELATED TO-AMENDMENT NO. 77TO :FACILifY OrERATING LICENSE NPF-9 AND AMENDMENT NO. 58-TO FACILITY OPERATING LICENSE NPF-17 1
DUKE POWER COMPANY.
i DOCKET NOS. 50-369 AND-50-370_
McGUIRErNUCLEAR STATION, UNITS 1 AND 2 INTRODUCTION ByletterdatedJune3,.1987, Duke: Power' Company)(the-licensee)Eproposed-amendments to revise Technical Specification-[TS 3/4.1.3 " Movable: Control.
R Assemblies" and its associated BasesL3/4.1.3. ~The change allows-tne unit to remain at power (Modes 1 or.2) for-up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with more than..one full-length rod inoperable but =trippable.
Prior to this change, the TS did not distinguish:
between immovable rods and immovable' but trippable: rods and with more than one.
full-length control rod innovable, the unit was required by' Action Statementsito be in hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
The specific t.hange is ' implemented by deleting " inoperable" from Action Statement-H b (which presently addresses both inoperable or misaligned rods), and addressing; the " inoperable" requirement separately in a new Action Statement:d. 'New(Action Statement d requires that, with more than one. full-length rod 'trippable'but~
inoperable due to causes other. than being innovable as-a resultiof excessive-friction or mechanical interference or known to be untrippable, power operation.
may continue provided that:(1) within'one. hour, the remainder of.the ~ods in r
the bank (s) with the inoperable rods are aligned to within t12-steps:of the inoperable rods while maintaining the rod sequence.and insertion limits-of TS Figure 3.1-1, and providing that (2) thermal power level'is' restricted pursuant to TS 3.1.3.6 during subsequent! operation.' These two provisions si
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regarding the remainder of the rods correspond.to'tb previous and unchanged requirements of -Action' Statement c which addresses no more than-one full-length rod trippable but inoperable for the same causes. New Action Statement'd also includes a provision that (3) the inoperable rods' are to be returned to operable-status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The amendments also delete' reference to Figure 3.1-21 in~ Action Statement c.
EVALUATION 3
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.By letter dated December 31, 1984, Westinghouse reconnended. generic revisions to TS 3/4.1.3 and its Bases regarding~ multiple immovable, but trippable,-
control rods. -Westinghouse noted the experience at several different plants with its NSSS in which a group or several groups of control rods became innovable. (would-not step -in or out) because of a rod control system; failure. The licensee cited similar experiences during control rod movement:
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. periodic tests in which control malfunctions prohibited a control rod bank or group from moving when selected, including a recent occurrence at Catawba Unit 2 when a fuse blew in the rod control circuitry.
In all cases, the rods were still trippable. (i.e., these rods would have been inserted into the core in the event of a reactor trip signal and, thus, were fully _ capable of performing their intended safety function of shutting down the reactor). The NRC has previously accepted the Westinghouse recommended generic rtvision and has incorporated the change into the TS of several operating plants (e.g.,
Diablo Canyon and Joseph Farley) and into a proposed revision to the Standard Technical Specification (NUREG-0452).
The additional time provided by the change to find and repair the cause of the rods' inoperability is justified because the rods are trippable.
l TS 3.1.3.1, as revised by these amendments, continues to provide requirements l
l to ensure that:
(1) acceptable ' power distribution limits are maintained, (2) the minimum shutdown margin is maintained with Jilowanceforastuckrod,(3) the potential effects of control rod misalignment on the associated safety analyses are acceptable, and (4) the trip reactivity assumed in the safety analysis will be available. Specifically, the revised TS requires that within one hour after entering the Action statement, the remainder of the control rods in the bank (s) with the inoperable rods are to be aligned to within 12 steps of the inoperable rods. This relates to ensuring confomance to items i
1 and 3 above.
Further, it is explicitly specified that the rod sequence and rod insertion limit TSs are to be maintained as applicable.
This ensures confomance with items 2 and 4 above.
The effect of the above TS changes is to allow continued operation in the j
event of electrical failures which prevent movement of more than one control rod. Since the rods remain trippable and thus are capable of providing their safety function in shutting down the reactor, the changes have no adverse l
impact upon safety and are, therefore, acceptable.
In Attach:nent C to a letter dated December 21, 1984, from E. P. Rahe, Jr.
(Westinghouse) to C. O. Thomas (NRC), a description of the movable control rod assembly mechanisms is provided along with a discussion of failures which may occur.
This material provides guidance on the type of electrical failures which may render the control rod assemblies inoperable but still 4
trippable. The licensee has referenced this material in the revised Bases 1
3.1.3.1 as previously requested by the staff.
i Reference to Figure 3.1-2, which had been left blank pending NRC approval of three-loop operation, is deleted from TS 3.1.3.1 for consistency with TS i
l 3.4.1.1 which prohibits part-loop operation, and because (as noted during prior Amendments 65 and 46) no approval of three-loop operation is pending.
l This administrative change has no adverse safety implication and is, therefore, acceptable.
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. ENVIRONMENT'AL CONSIDERATION These amendments involve changes to the installation or use of facility com-ponents located within the restricted area as defined in 10 CFR Part 20. The staff has determined that the amendments involve 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 exposure. The NRC staff has made a determination that the amendments involve no significant hazards consideration, and there has been no public comment on such finding. Accordingly, the amendments meet the eligi-bility 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 these amendments.
CONCLUSION The Commission made proposed detenninations tha't the amendments involve no significant hazards consideration which were published in the Federal Register (52 FR 26584) on July 15,1987 and (52 FR 9566) on March 25, 1987.
The Coninission consulted with the state of North Carolina.
No public comments were received, and the state of. North Carolina did not have any conunents.
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 comoliance with the Coninission's regulations, and the issuance of these amendments will not be inimical to the coninon defense and security or to the health and safety of the public.
Principal Contributors: Darl S. Hood, PDII-3/0RPI/II L. Kopp, SRXB Dated: November 5, 1987
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DATED:' November 5, 1987 i
l AMENDMENT N0. 77 TO FACILITY OPERATING LICENSE NPF McGuire Nuclear Station. Unit 1 l
AMENDMENT NO. 58 TO FACILITY OPERATING LICENSE NPF McGuire Nuclear Station, Unit 2 l
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DISTRIBUTION-I iDocket File 50-369/370 i
NRC PDR Local PDR PRC System l
NSIC PDII-3 Reading-b0uncan DHood HThompson OGC-Behtesda EJordan LHarmon WJones TBarnhart(8)
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LFMB NThompson LKopp l
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