ML20125C568

Summary of 780126 Meeting W/Nsp & GE Re Proposed Plant Spent Fuel Pool Expansion

ML20125C568
Person / Time
Site:	Monticello
Issue date:	02/03/1978
From:	Snaider R Office of Nuclear Reactor Regulation
To:	Desiree Davis Office of Nuclear Reactor Regulation
References
NUDOCS 9212110236
Download: ML20125C568 (8)

Text

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UNITED STATES NUCLE AR REGULATORY COMMISslON e

.t W ASHING TON, D. C. 20555

%,],+o February 3,1978 Docket No. 50-263 MEMORANDUM FOR: Don K. Dayts, Acttng Chtef Operating Reactors Branchf2, D0R FROM:

Richard P. Snaider, Project Manager, Operating Reactors Branch #2, DOR

SUBJECT:

SutttARY OF MEETING WITH NORTHERN STATES POWER COMPANY AND GENERAL ELECTRIC COMPANY REGARDING THE PROPOSED MONTICELLO SPENT FUEL P0OL EXPANSION On Thursday, Januar 26, 1978, representatives of the Northern State.e PowerCompany(NSP)ystaff and the General Electric Company (GE) staff met with the NRC staff to discuss outstanding items concerning criticality calculations for the proposed expanded spent fuel pool at the Monticello Nuclear Generating Plant. A list of attendees and the slides used during the presentation are enclosed.

The NRC request for a technical specification on uranium loading in new fuel was discussed.

It was the NRC contention that this specification supplements the existing requirement to assure that a pool Keff of 0.95 will not be exceeded in the future. The NRC l

staff expressed concern that an increase in uranium 235 loading

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increases the uncertainties in the calculations for the maximum Keff in the fuel and that these increased uncertainties should i

be evaluated by NRC when they occur.

GE and NSP contended that the proposed specification was in fact redundant to the Koff 10.95 requirement, and that other parametric variations could also result in Keff increases.

GE also noted that the subject of fuel pool criticality impact is reviewed upon any fuel redesign. They specifically referred to the latest GE topical submittal NED0-240ll. This document discussed a new design 8 x 8 fuel that is due to be used later this year.

1 After lengthy discussion, the NRC s;aff concluded that the specifi-cation of maximum uranium loading would not be necessary for l

l Monticello. This is partly because of the existing specification limiting Keff to < 0.90 (other plants use 0.95) and partly because of a future Regulatory Guide, presently under NRC staff review, into which the staff will incorporate requirements for submittal of necessary information to allow staff review and assure that the 9212110236 780203 PDR ADOCK 05000263 P

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.r-p criticality parameter remains within limits. The NRC staff stressed that this withdrawal of the requirement for augmented s pecifications

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applies only to Monticello. The NRC staff review has s%wn that l

other plants could indeed, given the right combination of fuel loading, errors, and uncertainties, reach or exceed their specified criticality limits.

The remainder of the discussion dealt with the model used for fuel cell and water gap parameters for criticality calculations in the i

GE model, especially under eccentric bundle and abnonnal pool loading conditions. The NRC staff stated that more information was needed on the actual cell to be used and its dimensions, bias and uncertainty values used in the calculational models, and gap dimensions used in modles to detennine criticality under abnomal conditions. NSP and GE committed to provide this information, N

Origina,,1 s%ned W (Qlph Richard P. Snaider, Project Manager j

Operating Reactors Branch #2 Diviti m of Operating Reactors

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Attachments:

1.

Attendance List 2.

GE Slides i

l DISTRIBUTION:

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t 5n.2 NRC POR Local PDR ORB #2 Reading NRR Reading B. C. Rusche i

E. G. Case V. Stello K. R. Goller i

D. Eisenhut T. J. Carter A. Schwencer G. Lear R. Reid W. Butler I-B. Grimes

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Project Manager -

R. Snaider Attorney, OELD -

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R. Diggs NRC Participants (Major) l R. Fraley, ACRS (16) j' T. 3. Abernathy, DTIE l

J. B. Buchanan i

Licensee i

B. Morris i

J. Gianelli-l E. Lantz I

R. Stanford C. Herrington, GE R. Stirn, GE P. Henrickson, GE i

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MONTICELLO SFP MEETING 1/26/78-NRC R. Snaider B. Morris J. Giannelli E. Lantz R. Stanford 4

NSP M. Voth G.E.

C. Herrington R. Stirn P. Henrikson i.

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mU235, SA TY l.IMIT FOR EACTIVITY 0

PURPOSE TEG SWCS INTEGRITY RADICACTIVE f%TERIALS BOUNDRY SETTING ENSURES SAFETY LIMIT NOT REACHED PRESENT SAFETY LIMIT KEFF <.95 O

EQUIRBeffS TEG S CS DIFFERENCES INDIVIDUALLY JUSTIFIED VARIABLES IDENTIFIED & JUSTIFIED REFERENCE SAFETY ANALYSIS-EVALUATION BASIS = DETAILS, FUU.Y DEVELOPED LEGAL STATUS - SAFETY ANALYSIS SUPPORT-i RATIONALE FOR BASIS 0

FIEL DESIGN OWEES REVIEW - GENERIC RELOAD FUEL APPLICATION l

I REACTIVITY'0F FUEL IN STORAGE -*

SPECIFIC PUNT REL(MDS '

TECH SPECS NOT PROPER DOCLNENT 4

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L-l WHY-THERE ISN'T A NEED FOR PROPOSED TECH SPEC.

CURRENT TECH. SPEC. LIMIT OF k.,10.95 l-e l

INCLUDES PROTECTION AGAINST AL.

ATTICE DESIGN CHANGES-4 e

U-235 w/o PER CM 0F BUNDLE LENGTH IS JUST ONE OF-MANY DESIGN PARAMETERS AFFECTING l-BWR LATTICE REACTIVITY j

e RELOAD LTR (NED0-24011-P) EVALUATES ALL RELOAD BUNDLE DESIGNS AGAINST FUEL STORAGE REQUIREMENTS e'

THE TECH, SPEC SHOULD PROTECT AGAINST ANY LATTICE CHANGE, NOT JUST FISSILE FRACTION I-1 1

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DESIGN PARAMETERS WHICH AFFECT BWR-lATTICE REACTIVITY-e BUNDLE AVEPAGE FISSILE-FRACTION o-FUEL R0D DIAMETER e

FUEL-R0D PITCH e

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GAD 0LINIA CONCENTRATION &' DISTRIBUTION.

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MAXIMUM INFINITE LATTICE REACTIVITY AT 65 C' BUNDLE TYPE MAXIMUM k_-

EXPOSURE (GWD/ST) 8D250 1,236

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