ML19345E781
| ML19345E781 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 07/22/1964 |
| From: | Boyd R US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| Shared Package | |
| ML19345E780 | List: |
| References | |
| NUDOCS 8102060101 | |
| Download: ML19345E781 (3) | |
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m HAZARDS ANALYSIS BY THE RESEARCH AND P0hTR REACTOR SAFITY BRANCH DIVISION OF RFACTOR LICE!: SING IN TEE MATTER OF CONSUMERS POWTR COMPANY BIG ROCK POIhT NUCLEAR PLAhT DOCKET NO. 50-155 PRCPOSED CHANGE NO. 2 - HIGH P0hTR DENSITY CORE OPERATION Introduction Censumers Power Company has requested, in letters dated March 26,196h, May 21, 196h, and TWI dated July 15, 196h, changes to the Technical Specifications to Operating License DPR-6 dated May 1,196h. Two of the proposed changes, items h7 and h9, involve source locations and start-up detector sensitivity during the period of operation with a hh fuel bundle high powcr density core instead of the :varmal 8h fuel bundle care. Item h6 relates to the source positions for the Bh bundle core and the cpera-tMnal start-up requirements for all start-ups, regardless of ccre size.
This change, designated Proposed Change No. 2, relates to items h73 h8 and h9 only.
Background
Se:. tion 8.0 of the Technical Specifications appended to License No. DPR42, dated May 1,196h, specifies operating limits during Phase II Research and Develorr:ent testing at the Big Rock Point Nuclear Plant. The range of vari-ables is described in Section 8.2.1.
Section B.2.2.2 authorizes changes to the core configuration to permit operation at average power densities as high as 60 xw/ liter in contrast to the no:nal value of h6 kw/ liter at 2hD MR(t) with 8h fuel bundles. Consumers, based on experience with a 56 bundis core during previous operation when reactor power was limited to 157 MR(t), has propcsed (item h7) to relocate the two antimony beryllium sources frem pesi-tions approximately midway between the detectors at the outer edge of the core (02-59 and 09-52 as specified in Section 5.1.6) to positions directly in front of the start-up detectors in order to satisfy the minimum count rate of 3 cps with a 3:1 signal-to-noise ratio as specified in Section 7.6.2(d) of the Technical Specifications. The other changes (items hB and h9) propose that the requirement that approaches to criticality where Keff is greater than 0.970 be such that the relative change in count rate is greater than cre-half of the relative change in neutron population be replaced by a more functional requirement.
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. A review cf test data presented by Consumcrs in report dated Novedber 26, 1962, supports the premise that the detectors are more insensitive to core neutron population when the sources were placed between the core and detector, as evi-denced by the withdrawal of adjacent poison rods with a resultant pronounced effect on the local neutron population, and, with respect to core neutron popu-lation, a disproportionately large detector signal chance.
Consumers has proposed, by TKX dated July 15,196h, additional cold physics tests with the high power density hh bundle. core to optimize both the location of the sources and the detector sensitivity to core neutron population changes during start-up.
Evaluation The purpose of the special tests to be perfonmed during the cold physics tests is to optimize source locations and the kh bundle core geometry to obtain opti-
. mum detector response. The tests are to be conducted with 2 or more CIC'c in the vessel to provide overpower protection using increased detector sensitivity to compensate for signal attenuation between the core and shield tank due to reduced temperature and small core. Start-up data for selected rod withdrawal sequences will be obtained fors 1.
syr:metrica11y loaded hh bundle core with sources at positions 02-58 and 9-53.
2 symmetrically loaded hh bundle core with sources at positions 2-53 and 9-58.
3.
skewed core one grid position northwest of centered core position with sources at positions 1-58 and 8-53.
h.
same skewed core as in 3 above with sources moved to positions 1-53 and 8-58.
It is expected that the tests will yield mlevant infomation which will be necessary to establish the optimum core arrangement and source location to meet minimum source level eps and provide a start-up signal proportional to neutron population. We believe that the experimentation described is necessary and may be performed safely.
By monitoring the start-up detectors and controlling reactivity insertion rates to obtain at least two decades of overlap between B o nd CIC sensors, there is l a an opportunity to detect abnormal responses and take appropriate corrective action before entering the power range. These considerations are applicable to all reactor startups, regardless of core size.
Consume rs reports, in item LB of the May 21,196h letter, that the source posi-tions for the Bh bundle core have been established at positions 02-59 and 09-52.
Accordingly, it is appropriate to now delete the second sentence of the first full paragraph of Section 5.1.6 of the Technical Specifications which allowed the selection of positions 02-52 and 09-59. Additionally, Section 7.3.2(e),
which relates to the increase in reactivity as a function of observed count rate, may be modified as discussed in the previous paragraphs of this analysis to per-tain to both the Bh and hh bundle cores.
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% Technical Specifications To provide authorization of Proposed Change No. 2, identified as items h7, hB, and h9, the Technical Specifications of License DPR-6 should be changed as follows:
1.
Section 8.2.2.2 add a new paragraph:
"For use with this small core, the source' positions as specified in 5.1.6 will not apply. The source positions are to be identified after special source location optimization tests, part of the cold physics tests, are completed and the data and evaluation have been reviewed and approved by the Commission. The suitability of use of in-core fission counters for monitoring start-up shall also be evaluated usirs data ob-tained during the cold physics tests. It shall be permissible to con-struct and test a skewed M bundle core for the purpose of determiring an ortimum source-chamber geometry."
2 Section 5.1.6, delete the second sentence of the first full paragraph.
3.
Section 7.3.2.(e), revised in its entirety:
" Critical approaches shall be monitored using the start-up detectors.
The start-up rate shall be restricted to assure that the CIC picoam-meters overlap the B10 start-up counter upon reaching approximately 10-7.T of rated ' power and are operational before attaining criticality.
Rod withdrawal sequence shall be specified and limited to that shown by previous analysis to preserve fuel integrity in the event of accidental continuous reactivity insertion."
Conclusion On the basis that cold pnysics tests will provide data to justify the relo-cation of sources for the high average power density, hh bundle core tects, and confirm that start-up detector nonitoring will assure sufficient instra-mentation overlap, we have concluded that the Technical Specifications of Licenae DPR-6 should be revised as indicated above to permit high averrge power density tests. Proposed Change No. 2 represents no significant hstard condition not described or implicit in the hazards summary report and there is reasonable assurance that the health and safety of the public will not be endangered.
Original signed by:
llager S. Boyd Roger S. Boyd, Chief Research & Power Reactor Safety Branch Division of Reactor Licensirg Date: July 22, 196h
DOCEET No. 50-155 July 22,196h USAEC DR. R. L. DOAN, DIRECTOR DIVISION OF REAGTOR LICENSING WASHINGTON 25, D. C.
CHANGE NO. 2 COIGUMERS P0h'ER COMPANY 212 WEFr.MICEIGAN AVENUE JACKSGI, MICHIGAN ATIN:
H. P. GRAVES GENERAL COUNSEL REURLTRS 3/26/6h, 5/21/6h AfD TWX OF 7/15/6h CONCERNING THE BIG ROCK POI!E NUCLEAR PLANT, DETERMINATIQi HAS BEEN MADE THAT YOUR REQUEST FOR CHANGE ITEMS NOS. h7, h8, AND h9, DESIGNATED CHANGE NO. 2 TO YOUR TECHNICAL SPECI-FICATIO!G, DOES NOT PRESEIE SIGNIFICANT HAZARDS CONSIDERATIONS NOT DESCRIBED OR IMPLICIT IN THE HAZARDS
SUMMARY
REPORT AND THAT THERE IS REASONABLE ASSUH-ANCE THAT THE HEALTH AND SAFETY OF THE PUBLIC WILL IUr BE ENDANGERED.
ACCORDIICLY, PURSUANT TO SECTION 50.59,10 CFR 50, THE FOLLOWING CHAfGES ARE MADE:
1.
SECTION 8.2.2.2, ADD A NEW PARAGRAPH:
"FOR USE WITH THIS SMALL CORE, THE SOURCE POSITIONS AS SPECIFIED IN 3.1.6 WILL NOI APPLY. THE SOURCE. POSITIONS ARE TO BE IDELTIFIED APIER SPECIAL SOURCE LOCATION OPTIMIZATIOw TESTS, (PART OF THE COLD PHYSICS TESTS,) ARE COMPLETE AfD THE DATA AND EVALUATION HAVE BEEN PEGEhTD AND APTR07ED BY THE CGTlSSION. THE SUITABILITY OF USE OF IN-CORE FISSION COUN'"ERS FOR MONITORING STARI-UP SHALL ALSO BE EVALUATED USING DATA OB-TAINED DURING THE COLD PHYSICS TESTS. IT SHALL BE PERMISSIBLE TO CON-STRUC2 AfD TE3T A SKEhTD hh-BUNDLE CORE FOR THE PURPOSE OF DETEFfl!ENG AN OPIIMUM SOURCE-CHAMBER GEG'ETRY."
2 SE0 TION 5.1.6. DELETE THE SECOND SENTE?CE OF THE FIRST FULL PARAGRAPH.
T/ol /s~oS7 6 MAoit6tvf
s' C073UMERS PG2R COMPANY 212 LTST MICHIGAN AVENUE JACKSON, MICHIGAN ATINs H. P. ORAVES GENERAL COUNSEL 3.
SECTION 7.372(e), REVISED IN ITS ETIRETY:
CRITICAL APPROACHES SHALL BE M0!HTORED USIIG THE START-UP DETFCTOF.S.
THE ST/RI-UP RATE SFJJL BE RESTRICTED TO ASSURE THAT ThT CIC PICO/JI-
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METERS OVERLAP THE B
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10 10-7% OF RATED POfER A!O ARE OPERATICNAL BEFORE ATTAINING CRITICALITY.
RCD WITIDRD?AL SEQUEL.CE SHALL BE SPECIFIED AND LIMITED TO THOSE SEQUE CES SHOG BY PRE"lIOUS ANALYSIS TO PRESERVE FUEL IhTEGRITY IN THE EVETI 0F ACCIDFl,TAL CONTINUOUS REACTIVITY I!GERTION."
CONFIFFING LFITER AfD HAZARDS ANALYSIS CONCERNING THIS CHA!0E WILL FOLLC1 BY I/ AIL. MO.
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