ML20002D097
| ML20002D097 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 07/21/1967 |
| From: | Skovholt D US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Haueter R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8101190434 | |
| Download: ML20002D097 (3) | |
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DRL Reading Branch Reading Public Document Room ACRS Tm Ltr (3)
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P. A. Morris, DRL D. J. Skovholt, DRL J. J. Shea, DRL Torral S. levine, DRL g 2 ; 1937 Docket 1:o. 50-155 Consu crs Power Ccepany 218 West Michiran Avenue Jackson, Michiran 149201 Attention: Mr. Robert L. Haueter Assistant Electrical Production Superintendent Gentle"en:
Pm;osed Chance No.13 to the Technical Specifications of License DPR-6, Docket !!o. 50-155, sulritted by your letter dated May 26, 1967, describes six new " center-melt" fuel bundles to be inserted into the Big Rock Point reactor and proposes power operating limits for these special fuel bundles.
By telephone on June 5, 1967, Consumers Power Company was notified that our review of the proposed change to the Technical Specifications could not be ccepleted by June 12, 1967, as requested, in time to permit inser-tion of the six " center-melt" fuel bundles during the current refueling outare.
On June 27, 1967, we met in the Bethesda offices of the regulatory staff with representatives of the Consumers Power Company of Michigan ard General Electric Company to discuss the pmposal and e<pand the evaluation in selected safety related areas. As a result of this meeting, we have pre-pared the enclosed list of iters which must te resolved before we can con-tinue our evaluation of your proposal to operate the Big Rock Point reactor with " center-relt" fuel in six special fuel bundles, described by you as "interrediate perforrance fuel" with incipient central melting and " advanced perforrance fuel" with definite but :roderate centrul UO2 fuel melting.
Answers to the enclosed items should be eulnitted as a supplerent to your Pmposed Change No.13. 'Ihree signed copics and 37 additional copies should be supplied.
S g4 y yours,
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DRL ter DRL DRL DRL i
Shea:bsp ury SImvine DJSkt it L
rrik ts and Qu< stions Donald J. Skovbolt sum Q 1 ed to Reactor Assistant Director for Reactor Operetions Div-~Ision cTReactor Licensinn tion witFH51}en tw w= nc.mii. dual....
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ADDITIONAL INF01CtATIOf: RE0VIRED IN SUPPORT OF PROPOSED O!AfGE !!O. 13 10 CONSUttERS POWEP. COMPRPI OT FICHICAN TTfHNICAL SPECIFICATION IVR BIG ROCK POIPTT PJ/CTOR IN CHARLEVOIX COU!TIY. MICHICAf' 1.
Fcactivity Insertion Accidents 1.3
- c was prtviously reported (supplerrent to BiF Rock Point Technical Specification Chanre No.10) that a gmvity drop of a md worth.04 delta k/L could cause a rnaximurn vertical displacerent of tim vessel of 0.17 ft and 0% raxinrn vessel strain. The corresponding liritinc red wrth value for the md ejection accident was reported to be.02 delta k/h.
Ih: have these lir.itine md worth values changed kr the "C" core with and without the proposed special " center-trelt" fuel bundles as a result of the rnore realistic analysis which prevents the second power burst due to the stearn explosion in the vicinity of the dispersed hirh enthalpy fuel rods?
1.2 A possibility exists that the very high enthalpy states in the " center-rnelt fuel" bundles adjacent to the dropped control red could cause extensive core daraFe impairing the control red scrwn and core cooling capability. Please discuss the analytical rnethods and test results which assure that corn geanctry is preserved following control rod drop accidents with red worths as high as.025 delta k/k.
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1.3 What is the flux suppression factor at the center of the " center-rnelt fuel" rods, particularly the 0.700 inch diarreter fuel rods, and how is the fd enthalpy gradient across the fuel rod cross nection con-sidered in assessine the extent of fuel and core damre?
2.
Loss of Coolant Accident It has been stated in Proposed Change No.13 that, as a consequence of the duration of the postulated primary system blowdown (Freater than 4 seconds) and the high heat tmnsfer rates expected in the core during blowdown, the center-rnelt fuel rod tempemtures will be reduced to a level characteristic of the ensuing decay power genemtion and are thus virtually independent of the initial stored energy content. The fuel, however, heats up again during the time interval of film blanketing following the blowdown and until core l
cooling is effective.
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2.1 Please discuss tle analytical metlods arr* input assumptions for 1
deterrinine peak fuel md temperatures, and present corparative i
maximum temperatures for "C" and " center-nelt" fuel rods after the MCA until the temperature rise has been arrested by fire main water spmyed onto the com via a sing,le spray header inside the
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reactor vessel.
2.2 Indicate the sensitivity of the fuel red terr.pemtures to duration of bloWown and core spmy initiation delays.
2.3' Discuss the applicability of tic tt:st data presented in Tirure 25 of the referenced proposal, which is bas <2d on initiation of core cooline, (core spray) before feel temperatums reach 12500T.
2.4 Present clad stresses during thu cociant blowdown period when the fuel rods are beint mpidly cooled by ejected prirrary coolant.
3.
Multi-Rod Critical Heat Plux Correlation i
Please justify the use of the new Gr. !!ulti-Pod Critical Heat Flux Correlation in calculatinr, " center-melt fuel" core perforrance limits, considerinr, the spiked armnrement of the center 4 melt fuel rods witidn the bundles where power ratios of adjacent rods are approxirately 18:1 in contrast to the norral situation where adjacent fucl rod power ratios o
are nearer to 1.
4 Calculational Accuracy It has been stated that axial power shapes for the "centerwmelt fuel" I
bundles are known within 5% and that radial power shape for tle hiF ly h
enriched fuel spiked with depicted fuel rods has an uncertainty factor of 10%. Are tiese uncertainty factors included in the fuel temperature
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calculations during accident conditions,&the perfomance lirits based on minimum cistical heat flux ratio of 1.5 at 122% overpcser?
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