ML20236Q481
| ML20236Q481 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 11/13/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20236Q473 | List: |
| References | |
| NUDOCS 8711200083 | |
| Download: ML20236Q481 (3) | |
Text
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goasog je UNITED STATES g
NUCLEAR REGULATORY COMMISSION n
WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0. 33 TO FACILITY OPERATING LICENSE NPF-35 AND AMENDMENT N0. 24 TO FACILITY OPERATING LICENSE NPF-52 DUKE PCWER COMPANY, ET AL.
DOCKET NOS. 50-413 AND 50-414 CATAWBA NUCLEAR STATION, UNITS 1 AND 2 INTRODUCTION By letter dated June 3, 1987, Duke Power Company, et al., (the licensee) pro-posed amendments to revise Technical Specification (TS) 3/4.1.3 " Movable Control Assemblies" and its associated Bases 3/4.1.3.
The change allows the 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 immovable, the unit was required by Action Statements to 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 change is implemented by deleting " inoperable" from Action State-ment 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 immovable as a result of excessive friction or mechanical interference or known to be untrippable, power operation may continue provided that (1) within one hour, the remainder of the rods in the bank (s) with the inoperable rods are aligned to within 112 steps of the inoperable rods while maintaining the rod sequence and insertion limits of TS Figure 3.1-la or Figure 3.1-Ib, as applicable, and providing that (2) thermal power level is restricted pursuant to TS 3.1.3.6 during subsequent operation. These two provisions regarding the remainder of the rods correspond to the 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 />.
Furthermore, Action Statement C.2 was revised to change " Figure 3.1-1" to " Figure 3.1-la or Figure 3.1-lb, as applicable."
EVALUATION By letter dated December 31, 1984, Westinghouse recommended generic revisions to TS 3/4.1.3 and its Bases regarding multiple immovable, but trippable, con-trol rods. Westinghouse noted the experience at several different plants with its Nuclear Steam Supply System (NSSS) in which a group or several groups of control rods became immovable (would not step in or out) because of a rod con-trol system failure. The licensee cited similar experiences during control rod movement periodic tests in which control malfunctions prohibited a control rod bank or group from moving when selected, including a recent occurrence at B711200083 B71113 h
PDR ADOCK 05000413 P
... F the rods were still trippableCatawba Unit 2 when a fuse blew
- rcuitry, in all cases, the core in the event of a rea,ctor trip signal and(i.e., these rods wo performing their intended safety function of shutting d, thus, were NRC has previously accepted the Westinghouse recommend dow The has incorporated the change into the TS of several o e
generic revision and Diablo Canyon and Joseph Farley) and into a proposed re i ipe Technical Specification (NUREG-0452 v s on to the Standard change to find and repair the cause)o. The additional time provided by the because the rods are trippable.
f the rods' inoperability is,iustified TS 3.1.3.1, as revised by these amendments, continues t to ensure that:
the minimum shutdown margin is maintained with allo (1) the potential effects of control rod misalignment on thwance for a stu
, (2) analyses are acceptable, and (4) the trip reactivity assumed ie a analysis will be available.
one hour after entering the Action statement, the remaind n the SE fety rods in the bank (s) with the inoperable rods are to b steps of the inoperable rods.
e control e aligned to within 12 Further, it is explicitly specified that the rod s 1 and 3 above.
rod insertion limit TSs are to be maintained as applicabl conformance with items 2 and 4 above.
ence and e.
This ensures The effect of the above TS changes is to allow continued event of electrical failures which prevent movement of more th operation in the rod.
Since the rods remain trippable and thus are capable safety function in shutting down the reactor, the changes have an one control impact upon safety and are, therefore, acceptable of providing their no adverse In Attachment C to a letter dated December 21 (Westinghouse) to C. O. Thomas (NRC), a description, 1984, from E rod assembl may occur. y mechanisms is provided along with a discussion o of the movable control failures which may render the control rod ass mbliThis m trippable.
r cal 3.1.3.1 as previously requested by the staffThe licensee has e
sed Bases ENVIRONMENTAL CONSIDERATION These amendments involve changes to the installation ponents located within the restricted area as defined in or use of facility c staff has determined that the amendments involve no significa n 10 CFR Part 20 The the amounts, and no significant change in the types be released offsite and that there ncrease in
, of any effluents that may cumulative occupational exoosures. is no significant in the amendments involve no significant hazards co no public comment on such finding.
nsideration, and there has been bility criteria for categorical exclusion set forth accordingly, the amendme Pursuant to 10 CFR 51.22 b) no environmental impact n 10 CFR 51.22 assessment need be prepar(ed in cornection with the issua statement or environmental e of these amendments.
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$9pjLjlSION The Cumission rede a proposed determination that the amendments involve no i
i s1 olficant hazards consideration which was published in the Federal Register 9
(52 FR 26584) on July 15, 1987.
The Commission consulted with the state of~
South Carolina. No public comments were received, and the state of South Carnlina did not have any connents.
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 j
will be conducted in compliance with the Commission's regulations, and the 1
issuance of these amendments will not be inimical to the common defense and I
security or to the health and safety of the public.
l Principal Contributors:
Kahtan N. Jabbour, PDII-3/DRPI/II L. Kopp, SRXB Dated:
November 13, 1987 I
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