ML20002C839
| ML20002C839 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 05/18/1977 |
| From: | Bilby C, Bixel D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Desiree Davis Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20002C840 | List: |
| References | |
| NUDOCS 8101120146 | |
| Download: ML20002C839 (5) | |
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CORSumBIS
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-a iLL; General Offices: 212 WcSt Michegsn Avnnue, Jac kson, MicNgan 49201. Area Code S17 7RR OSSO May 18, 1977
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7h,t' Director of Nuclear Reactor Regulation 7
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DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLAST - REQUEST FOR TECHNICAL SPECIFICATIONS CHA"GE: MAXIMUM WINCH SPEED Transmitted herewith are three (3) executed and thirty-seven (3T) conformed i
copies of a request for a Technical Specification: enange of License DPR-6, Docket 5C-155, issued to Consumers Power Co=pany on May 1,196h for the Big Rock Pcint Plant.
This proposed change, when approved, vill delete the 100-inch per minute limitation on vinch speed for refueling operations. This vill allow the replacement of the undersized 1/L-ton vinch currently mounted en the trans-fer cask with a 1-ton vinch.
Refueling operations at Big Rock Point are currently expected to begin in early June 1977 Therefore, approval of this Technical Specifications change is re-quested by June 8, 1977 m~
David A Bixel Nuclear Liceasing Administrator CC:
JGKeppler, USNRC 4
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CONSUMERS POWER COMPANY Docket 50-155 Request for Change to the Technical Specifications Licenst DPR-6 i
For the reasons hereinafter set forth,'it is requested that the Technical Specifications contained in Provisional Operating License DPR-6, Docket 50-155, be changed as described in Section I, below:
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Changes j
A.
Delete Section 6.3.2(b).
B.
Delete "...and travel speed controls..." from Section 6.3.3(b).
NOTE: Corrected Technical Specifications page is included as Attachment 1 to this submittal.
II. -Discussion Historically, the vinch used at Big Rock Point for refueling operations is an undersized 1/h-ten vinch sounted on the fuel transfer cask. This vinch is used to raise or lover fuel bundles of a nominal weight of 450 pounds. Past testing on the vinch has shown that it is capable of lifting 1,250 pounds, and an identical vinch has liftec 3,000 pounds with no adverse effects. Further, current procedures call for testing the vinch to 750 pounds prior to cccmencing refueling operations. However, since the nc=inal weight of a fuel bundle is h50 pounds, with the possibility of extraction (friction) forces adding to the total weight, there existed a chance of exceeding the design rating of the vinch. 'This appeared to be of_little concern based on the performance of the vinch to date. However, to be absolutely certain of the continued performance 4
and safety of the vinch, the vendor was contacted and attempts. vere made to up-
. grade the' capacity. These efforts proved futile; the vendor could not guaran-
-tee the performanre of the vinch above the rated 1/h-ton capacity. Therefore, Consumers Fover Company was forced to discontinue the use of the 1/h-ton vinch in fuel handling activities, and a new 1-ton vinch was obtained. The 1-ton vinch will be under the same operational and administracive eontrols as those
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1, governing the 1/L-ton vinch. There.will be an overload switcP that de-energizes the vinch once high extraction forces are encountered. The
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current procedural limit is 750 pounds. Administratively, there is a 900-pound limit _on extraction force that the operator cay not exceed without prior approval of plant Management. Further, fuel design studies have shown that the limiting component on the fuel bundle is the lifting bale on the tie plates. At 2-1/2 times the nominal weight of the_ fuel
. bundle (approximately 1,125 pounds) only one half the yield strength is reached.
(Ref: JN-72-15) Thus, there is adequate physical and admin-istrative limits ensuring that_ fuel extraction operations vill not reach or exceed design fuel bundle structural limitations. Testing on the 1-ton vinch prior to refueling operations will be consistent with those delin-eated (above) for the 1/h-ton vinch.
The 1/L-ton winch had a rated minimum speed of 8 feet per minute (hence the Technical Specifications limitation of 100 inches per minute). The minimum hoist speed available on the 1-ton vinch is 112 inches per minute. The ability to alter the gearing on the 1-ton vinch to meet the 100-inch per minute Technical Specifications limitation is not possible without major design modification.
l Thus, in order to use the 1-ton vinch, an extersive review of the basia for the 100-inch per minute limitation was cc 2aucted.
Consumers Power Company has concluded that the 100-inch per minate limita-tion on hoist speed is an arbitrary limitation based on the design speed of the original vinch, that accident analyses performed on the results of ex-J cessive hoist speed are bounded by other more limiting potential refueling accidents, and that other Technical Specifications limitations governing refueling operations negate the need for limiting hoist speed.
The original basis for the 100-inch per minute limitation on vinch speed is contained in the Big Rock Point Final Haza.-ds Summary Report, Sections 12 9 2.h, 12 9 3 and 12 9.h.
Section 12 9 2.h details the consequences of inserting a fresh fuel bundle in the core assuming k,ff '= 1.0, all control rods ere inserted, and an empty 2
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position exists in the lattice.
It is readily apparent that with the re-fueling interlocks and Technical Specifications limitations on shutdown margin and control rod coupling integrity, the conditions postulated for
- this analysis are simply not possible.
The analyses contained in Sections 12 9 3 and 12 9.h deal with the insertion of a fuel bundle at 100 inches per minute and with a fuel bundle drop, both under the cond', Lions postulated in Section 12.9 2.k.
These analyses are no longer required by current industry standards (ie, standard Review Plan, Regulatory Guides, etc). However, they do establish that the most limiting potential occurrence is the fuel bundle drop into the core. Thus, the ef-fects of increasing vinch.wsed by approximately 12% vould be negligible when compared to the effects of the limiting potential accident.
In order to ensure that all aspects of potential or postulated accidents involving reload vinch speeds are adequately addressed, the Nuclear Regulatory Commission Standard Review Plans and Regulatory Guides were re-searched.
The only documentation found that addressed this issue directly was Regulatory Guide 1.10h', " Overhead Crane Handling Systems for Nuclear Power Plants." This Regulatory Guide pointed out that a vital issue in determining vinch speed was crane operator response to abnormalities in the hoisting movement. At Big Rock Point the vinch operator stands on a platform directly above the fuel bundle to be moved.
He is in direct visual contact with the bundle at all times, has tools available to physically sense bundle movement, and is never more than 20 to 30 feet from it.
He is supplied with a dynamometer to adequately determine load and can readily cease vinch movement at any sign of abnormality by releasing the power switch. Thus, when the comparison is made between reload operations at Big Rock Point and at plants that, because of size, utilize large overhead cranes, Consumers Power Company concludes that the intent of Regulatory Guide 1.104 concerning vinch/ hoist speeds is adequately met, even with hoist speeds in excess of those specified in the Regulatory Guide.
If this Technical Specifications change request is not' grante,d prior to
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refueling operations scheduled for early June, certain modifications to 3
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existing equipment would be 'necessary, the critical path for subsequent reactor start-up would be extended and more fuel movement would be' required.
III.
Cone,1usion Based on the foregoing, both the Big Rock Point Plant Review Co=mittee and the Safety and Audit Review Board have concluded that this change does not involve an unreviewed safety question.
CONSUMERS POWER COMPANY
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.By C.R Bilb;7, Vice Prec$nt Production & Transmission Sworn and subscribed.to before me this 18th day of May-1977 I
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Idnda R Thayer, Not;/ry Vublic
-Jackson County, Michigan
.My commission expires July 9, 1979 C
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