ML20136B788

Forwards Safety Evaluation Approving Proposed Early Defueling Activities,Per 850520 & 1010 Requests.Activities May Commence Upon NRC Approval of Applicable Defueling Procedures Per Tech Spec 6.8.2

ML20136B788
Person / Time
Site:	Three Mile Island
Issue date:	11/12/1985
From:	Travers W Office of Nuclear Reactor Regulation
To:	Standerfer F GENERAL PUBLIC UTILITIES CORP.
Shared Package
ML20136B791	List: ML20136B788 ML20136B809
References
CON-NRC-TMI-85-089, CON-NRC-TMI-85-89 NUDOCS 8511200288
Download: ML20136B788 (2)

Text

- ----

DISTRIBUTION:

d v.; DN 50-320 J

NRC PDR Local PDR DCS TMI 11Q r/f TMI Site r/f November 12, 1985 WDTravers NRC/TMI 85-089 MTMasnik RAWeller PJGrant RCook Docket No. 50-320 CCowgill LChandler IE Hr. F. R. Standerfer ACRS Vice President / Director M-Town Office Three Mile Island Unit 2 Service List GPU Nuclear Corporation P. O. Box 480 Middletown, PA 17057

Subject:

Safety Evaluation for Early Defueling Your letter dated May 20, 1985, as revised by letter dated October 10, 1985, submitted the safety evaluation report (SER) for early defueling of the THI-2 reactor vessel and requested Nuclear Regulatory Commission (NRC) approval.

This-letter. provides NRC staff approval of your request and includes our-safety evaluation of the proposed early defueling activities.

By letter dated October 24, 1985 GPU requested NRC approval to conduct limited preliminary defueling activities inside the reactor vessel. Staff approval was granted in a letter dated October 29, 1985, with a supporting safety evaluation. As described in that approval letter, authorization was given for: 1) rearrangement of core debris within the reactor vessel to allow complete installation and rotation of the Canister Positioning System and to provideaccessfordefuelingtools,and2)identificationandpositioningof core debris samples in the vessel. It was also understood that general movement of coro debris could include the loading of debris baskets but that no defueling canisters would be loaded with fuel debris nor could there be any core debris removed from the reactor vessel. The conclusions of that safety evaluation and their bases also apply to all the defueling activities covered herein.

This letter and the attached safety evaluation address all proposed early

.defueling activities including the removal of accident generated core debris ,

from the reactor vessel and storage of that debris in defueling canisters placed in storage' racks located in the fuel transfer canal and "A" spent fuel pool. This also includes the use of two canister handling bridges (CHB) and a canister transfer system (CTS) which is used to transfer defueling canisters to the flooded deep end of the Reactor Building fuel transfer canal through the CTS to the Fuel Handling Building.

In our review, we considered the infomation provided in 1) the subject SER,

2) discussions with your staff, 3) responses to our docketed questions, and 4) 8511200288 51112 " - " " ""- "- " " " " " " " "

. . . . . . . . . . . . . ^==a5ago . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .

urc ronu ns oo-soi nacu ono OFFICIAL RECORD COPY

tir. F. R. Standerfer Hos: ember 12, 1985 /

e other related defueling documents some of which were subjects of separate NRC reviews and approvals (these are all referenced in the attached SER). We also observed testing and checkout of the major defuelino equipment and monitored your operator training program. Both canister handling bridges have been operationally inspected, load tested and subjected to a full integrated test.

Based on our reviews and as detailed in the enclosed safety evaluation we find that: 1) there is little' potential for core recriticality'due to fuel reconfiguration or a baron dilution event, and that the design of defueling canisters provides adequate assurance that loaded fuel will remain subcritical with a substantial shutdown margin for all postulated canister conditions; 2)

" loss-to-ambient" cooling of the RCS will provide adequate decay heat removal;

3) there is little potential for a pyraphoric reaction; 4) adequate methods of combustible gas control are provided through defueling canister design and dewatering and off-gas system operation; 5) appropriate measures for the handling of heavy loads have been implemented to minimize the probability and consequences of postulated accidents; 6) existing fire protection measures are acceptable; 7) there is little potential for a release of radioactivity significantly greater than the trace amounts which have been typically discharged throughout the cleanup; 8) there is little potential for worker overexposure and GPUN has implemented a program to maintain occupational exposures ALARA; and 9) early defueling activities do not constitute an unreviewed safety question. We also find that the proposed activities fall within the scope of those analyzed in the PEIS. We, therefore, conclude that the proposed early defueling activities can be safely conducted with minimal risk to the health and safety of the ensite workforce and offsite public.

Based on these findings and the NRC licensing of five (5) Fuel Handling Senior Reactor Operators (FHSRO's), we approve the proposed preliminary defueling activities described herein. These activities may commence upon staff approval of the applicable defueling procedures pursuant to Technical Specification 6.8.2. Additionally it should be noted that until we have taken action on the Heavy Load SER (Rev. 2) your are prohibited by your technical l specifications from lifting heavy loads over any defueling canisters which contain core debris.

Sincerely,

'MM0HED WNcm D. ha, William D. Travers Acting Director -

Tit! Program Otfice

Enclosure:

As stated cc: T. F. Demmitt R. E. Rogan S. Levin W. H. Linton J. J. Byrne A. W. Hiller Service Distribution List n (zno att2* hod \

ma> &p. .. .Wl.

%. .mf .

...T. . .. ..... . . - . .. - - -- --

g!

f w.85....

om> 11L%l85... ..'.ll!N85...

.'.ll - - - - -

d NRC FORM 318 (10 80) NRCM 0240 OFF C RFCORD COPY