ML18046B051

Advises That Util Must Use Approved Interim Method in Cycle 5 Reload Safety Analysis to Address Fuel Rod Bowing. Acceptable Means to Accommodate Thermal Reduction Margin Must Be Submitted

ML18046B051
Person / Time
Site:	Palisades
Issue date:	10/29/1981
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
References
LSO5-81-10-055, LSO5-81-10-55, NUDOCS 8111170134
Download: ML18046B051 (5)

Text

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, 0. C. 20555 Docket No. 50-255*

LS05-81.:.10-oss Mr.. David P. Hoffman Nuclear Licensing Administrator Consumers* Power Company*

i945 W. Parnall Road Jackson, Michigan 49201

SUBJECT:

PALISADES CYCLE 5 RELOAD October 29; 1981 Your reload safety analysis (Ref. 1) for Cycle 5 operation did not address fuel rod bowing.

Consequently, based on the current NRC approved method (Ref. 2), we constructed a table for gap closure and torresponding DNBR penalty as a function of fuel assembly burnup, transmitted a copy to you and asked you to submit an acceptable means of accommodating the thermal margin reduction.

You objected to our position of using the NRC-approved interim method which uses linear interpolation between zero and full contact for partial gap closure in determining DNBR penalty. Rather, using the Exxo~ Nuclear proposed DNBR reduction model (Ref. 3) which indicates no DNBR reduction for gap closure less t~an 50%, you contend that no DNBR penalty is required for Cycle 5.

We have found this argument not acceptable because the Exxon proposed model is still under rev.iew, c::urre'ntly being revfsed by Exxon, and is therefore not an approved method.

Consequently, we require that the approved interim method in Reference l be used for DNBR penalty calculations. However, we have also re-evaluated the DNBR penalty based on the current Palisades over pressure trip set point of 2255 psi a and the hot pin average heat flux of 0.3. x lob Btu/hr-ft2.

Using the maximum DNBR penalty for full contact as described. in Reference 3, a new DNBR penalty as a function of fuel burn-up is shown in Table 1.

Since the maximum burnup for Cycle 5 is 35000 MWD/MTU, a 7.9% DNBR penalty due to fu~l rod bowing is required.

You are, therefore, required to submit an acceptable means to accommodate this thermal margin r~duction.

In Reference 4, you claimed potential thermal margin credits from primary coolarit flow, core inlet temperature, spacer grids and most limiting anti-cipated transient analysis.

You must quantify the credits and justify the derivation of these ~redits from higher coolar:rt flow, lower core inlet temperature and limiting transient analysis.

If these credits

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Mr. David OCTOB£R 2 9 1981 are claimed, the Technical Specifications must have operating limits cbnsistent with the claimed credit. You also contend that the,

advantageous.effect.of spacer grids.on CHF.was.not included ir1 y~ur MDNBR ca1culations and. therefore, a thermal-margin credit exists *. *

~Je find this position unacceptab.le. since.the grid f!ffect on CHF is

• reflected in the data for the 1~.. 3 correlation development.

Please respond.to thjs letter on.a sbhedule consistent with your need for our approval. allowing at leasttwo weeks for our review.. Since this request is being.sent only to Consumers Power Company and relates to an approval.requested by Consumers Bower Company concerning*

an issue speci.ff c.to Palisades, no clearance from the Office of Management. (OMB) and Budget is required~

Enclosures:

1.- Reference Page

2. Table 1 cc w/enclosures:

See next page Sincerely.

ORIGINAL SIGNED BY Thomas V. Wambach D~nn1s M. Ctutchfield. Chief Operating Reactors Branch #5 Division of Licensing jliS.Il.UfilJT ION :

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NRC PDR LPDR TERA NSIC

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DCrutchfield GL*ainas TWambach HSmith

. CHarwood PWooley.

NRG FORM 318 (10-80) NRCM 0240 OFFICIAL RECORD COPY

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USGPO: 1981-335-960 ;

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Mr. David. P. Hoffman cc w/enclosures:

~M~ I. Miller, Esquire Isham, Lincoln & Beale Suite 4200 One First National Plaza Chicago, Illinois 60670 Mr. Paul A. Perry, Secretary Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Judd L. Bacon, Esquire Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Myron M. Cherry, Esquire Suite 4501 One IBM Plaza Chicago, Illinois 60611 Ms! Mary P. Sinclair Great Lakes Energy Alliance 5711 Summerset Drive Midland, Michigan 48640 Kalamazoo Public Library 315 South Rose Street

.Kalamazoo, Michigan 49006 Township Supervisor Covert Township Route 1, Box 10 Van Buren County; Michigan Office of the Governor (2)

Room l ~ Capitol Building Lansing, Michigan 48913 William J. Scanlon, Esquire

• 2034 Pauline Boulevard Ann Arbor, Michigan 48103 Palisades Plant ATIN:

Mr. Robert Montross Pl ant Manager Covert, Michigan 49043

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49043 October 29, 1981 U. S. Environmental Protection Agency Federal Activities B~anch Region V Offi.ce ATTN:

Regional Radiation Representative 230 South Dearborn Street Chicago, Illinois 60604 Charles Bechhoefer, Esq., Chairman Atomic Safety and Licensing Board Panel U. S. Nuclear Regulatory Co111Tiission Washington, D. c.

20555 Dr. George C. Anderson Department of Oceanography University of Washington Seattle, Washington 98195 Or. M. Stanley Livingstpn 1005 Calle L~rgo Santa Fe, New Mexico 87501 Resident Inspector c/o U. S. NRC Palisades Plant Route 2, P. 0. Box 155 Covert, Michigan 49043

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.1 REFERENCES

1.

XN-NF-Bl-34, "Palisades Cycle 5 Reload Fuel Safety Analysis Report,"

June 1981, Exxon Nuclear Canpany, Inc *

. 2.

.D. F. Ross and D. G. Eisen hut ( USNRC) Memorandum to D. B. Vassal 1 o and K. R. Goller, "Revised Interim Safety Evaluation Report on the Effects of Fuel Rod Bowing on Thermal Margin Calculations for Light Water Reactors" February 16, 1977.

• 3.

XN-75-32, Supplement 2, 11 Computation Procedures for Evaluation Fuel Rod Bowing" July 1979, Exxon Nuclear Canpany, Inc.

4.

D. P. Hoffman letter to A. Schwencer, Chief, Operating Reacto*rs Branch #1 (USNRC), "Palisades Plant Fuel Rod Bow - Thermal Margin Credits," dated February. 14,*1977, Docket 50-255.

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Ass~mbly Burnup.

(Gi~D/t) 0 5

10 15 20 25 30 35 40 TABLE 1 DNBR PENALTY Gap Closure

(%)

. 0

24. 1 30.0 34.5 38:3 41.6 44~6 47.4 50.0

.~

Reduction in DNBR

(%}

0 4.03 5.02

5. 77 6.41

. 6. 96 7.46 7.93 8.37