ML19326B427
| ML19326B427 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 03/04/1974 |
| From: | Phillips J ARKANSAS POWER & LIGHT CO. |
| To: | Knuth D US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19326B424 | List: |
| References | |
| NUDOCS 8004150785 | |
| Download: ML19326B427 (5) | |
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ARK ANS AS POWER & LIGHT COMPANY 97H G LOUIStANA GTAFETS . LsTTLE ACCK. A AK ANSAG 72203.(5013372-4391 March 4, 1974 Mr. D. F. Knuth Director of Regulatory Operations Office of Regulations United States Atomic Energy Commission Washington, D. C. 20545
Subject:
Arkansas Power 4 Light Company Arkansas Nuclear One-Unit 1 '
Docket No. 50-313 Change in Specific Hest of Uranium Dioxide
Dear Mr. Knuth:
On January 17, 1974, you were notified that B5W was revising the specific heat curve for UO 2 fuel as utilized in some of its transient computer codes for plant safety analyses. This revision was expected to increase 3
the values for specific heat at elevated temperatures. A new specific s heat curve has now been issued, following appropriate quality assurance and approval steps, and incorporated into the affected transient codes.
The new specific heat curve is attached.
The safety implications of higher values of specific heat were investi-gated by re-running the various transients. The slower transients were unaffected. The more rapid transients were investigated with the following results:
Rod Ejection Transient:
The DNBR was not noticeably affected. The maximum cladding temperature descreased by 70 F to 100 F and the maximum fuel temperature decreased by 200 F to 300 F.
Locked Rotor Transient :
The DNBR was not noticeably affected. The maximum cladding tem-perature increased by 5 F to 15 F and the fuel temperatures fell off at a slower rate. The overall effect of this change is insignificant.
Four-Pump Coastdown Transient:
'Ihe increased specific heat values had no significant effect on this transient.
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[ Mr. D. F. Liuth March 4, 1974 i
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ECCS Analysis:
The only impact the specific heat revision has on safety limits is th'e lowering of some portions of the allowable linear heat rate by up to 0.65 klf/ft. This LOCA-derived curve determines the allow-able linear heat rate as a function of elevation in the core. The revised linear heat rate is in compliance with the Interim Accep-tance Criteria. Revised LOCA limits were determined by repeating the Oconce 2 calculations because these analyses are representative of the 177 fuel assembly plants. The allowable heat rate curve on Oconce 2 is lower by 0.65 klf/ft at the 6-foot elevation but is unchanged at the 10-foot elevation. The, revised LOCA limit curve is attached. <
Reactor Building Pressure:
The initial stored energy in the core is increased by less than one million BTU's; calculation of the reactor building pressure shows no change.
A re-analysis of ANO-1 operating margins with respect to I!he revised LOCA n limit curve was performed based on the procedures developed in BA11-10076.
This analysis shows that the revised LOCA limit would have been violated (V) assuming the licensed design conditions early in life. Based on Oconce 1 and 2 operation, however, these design conditions are known to be conser-vative and an actual violation would have required the simultaneous existence of several " worst case" uncertainties. In order for ANO-1 to operate within the revised LOCA limit and more accurately reflect the operating characteristics of Oconee 1 and 2 experience to date, revised Technical Specifications will be submitted in the next three weeks for e
ANO-1.
Very truly yours, ,,
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7 J. D. Phillips Senior Vice President Attachments cc: Mr. Norman C. Moseley, Director Directorate of Regulatory Operations Region II United States Atomic Energy Commission 230 Peachtree. Street, N.lf.-Suite 818 Atlanta, Georgia 3030 l
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U STATE OF ARKANSAS )
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SS COUNTY OF PULASKI ,;
J. D. Phillips, being duly sworn, states that he is a Senior Vice President of Arkansas Power G Light Company; that he is authorized on the part of said Company to sign and file with the Atomic Energy Commis-sion this Supplementary Infomation; that he has read all of the statements contained in such Information, and that all such statements made and matters set forth therein are true and correct to the best of his knowledge, information and belief.
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& J. D. Phillips-O .
SUBSCRIBED AND SWORN TO before me, a Notary Public in and for the G 4 day of A.* -, J , 1974.
County and State above named, this
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