ML19319E480
| ML19319E480 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 08/26/1975 |
| From: | Cavanaugh W ARKANSAS POWER & LIGHT CO. |
| To: | Rusche B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML19319E475 | List: |
| References | |
| NUDOCS 8004110635 | |
| Download: ML19319E480 (1) | |
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'e H ELPIN G BUILO ARKANSAS ARK ANS AS POWER & LIGHT COMPANY STH C. LCulSIAN A ST AEETS. t_ITTLE ROCK. A AK ANS AS 72203.(5013372-4311 August 26, 1975 DwA
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Mr. B. C. Rusche, Director ry Office of Nuclear Reactor Regulation (24 >-
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Subject:
Arkansas Power 6 Light Company N./l/g.~
w Arkansas Nuclear One-Unit 1 Docket No. 50-313 License No. DPR-51 Unusual Event Report No. 50-313/75-2
Dear Mr. Rusche:
On June 25, 1975, we transmitted to you the subject report and informed
'y you of our re-evaluation study. The results of this study are currently s
under review and will be ready for submittal by September 8, 1975.
Ve truly yours, h,
William Cava ugh III Manager, Nuclear Servi s WC:lt cc: Mr. E. Morris Howard, Director U. S. Nuclear Regulatory Commission Office of Inspection & Enforcement Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76012 m&
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TAX P AYING. INVESTOR OWNEO MEMBER M100LE SOUTM IITIES SYSTEMSENT l
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.a H GL PIN G 93 U I L O A Li $t A f)., s} lj ARK ANS AS POWER & LIGHT COMPANY 9,H & LOUISIAN A S,A..,S LI,TL. ACCK. A AK ANS AS 72203.(5013372-4311 l
June 25, l
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DUPLICATE DOCUMENT Entire document previously entered into system under:
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// O h[ Q Mr. B. C. Rusche, Director ANO Office of Nuclear Reactor Regulation No. of ges:
U. S. Nuclear Regulatory Cc6aission Washington, D. C.
20555
Subject:
Arkansas Power G Light Company Arkansas Nuclear One-Unit 1 Docket No. 50-313 License No. DPR-51 Unusual Event Report No. 50-313/75-2
Dear Mr. Rusche:
Attached find our report concerning an Unusual Event related to Arkansas
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Nuclear One-Unit 1.
This report is submitted pursuant to Appendix A, Technical Specification 6.12.3.2.
Very truly yours,
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J. D. Phillips '
Senior Vice President i
JDP:lt Attachment cc: Mr. E. Morris floward, Director U. S. Nuclear Regulatory Commisison Region IV
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611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76012 (CSh}
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STATE OF ARKANSAS
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SS COUNTY OF PULASKI
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J. D. Phillips, being duly sworn, states that he is a Senior Vice President of Arkansas Power & Light Company; that he is authorized on i
the part of said Company to sign and file with the Nuclear Regulatory Commission this Supplementary Information; that he has read all of the I
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' J. D. Phillips
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r SUBSCRIBED AND SWORN 'ID before me, a Notary Public in and for tne 4
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County and State above named this/.5 2
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c :_ m Notary Pub 1'ic My Commission Expires:
March 1, 1978-I i
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Unusual Event Report No.
50-313/75-2 1
2.
Report Date:
June 25, 1975 3.
Occurrence Date:
May 8, 1975 1
4.
Facility:
Arkansas Nuclear One-Unit 1 Russellville, Arkansas 5~.
Identification of Occurrence:
Reactor Building Spray (RBS) System may not draw down uniformly as stated in the FSAR.
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Conditions Prior to Occurrence:
Steady-State Power Reactor Power MWth Hot Standby Net Output MWe Cold Shutdown Percent of Full Power Refueling Shutdown Load Changes During Routine Power Operation Routine Startup Operation Routine Shutdown Operation DUPLICATE DOCUMENT Other (specify)
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N o. of pages:
7.
Description of Occurrence:
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Analysis by Babcock 6 Wilcox of the hydraulic performance of the RBS under accident conditions reveals that the Sodium Thiosulfate and Sodium liydroxide Tanks may not draw down uniformly with the Borated Water Storage Tank.
It was, however, noted by BSW that this analysis was sensitive to the as-built piping configuration.
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Unusual Event Report No. 50-313/75-2 s_.
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Designatica cf Apparent Canse of Occurrence:
Design X
Procedure Manufacture Unusual Service Condition Including Environmental Installation /
Construction Component Failure Operator Other (specify) t 9.
Analysis of Occurrence:
The ' hydraulic performance of a RBS was analyzed following a LOCA (14.1 ft )
2 in the hot leg of the RCS. The situation was analyzed for the one and two header case (i.e., I and 2 LPI pumps, 1 and 2 HPI pumps, and 1 and 2 i
RBS pumps). The hydraulic resul s for the piping system show that:
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The Sodium Hydroxide and Sodium Thiosulfate tanks emptied before the Borated Water Storage Tank (BWST). Thus, there is no thiosulfate or hydroxide in the RBS from th'e' time the two chemical. tanks empty until the pump suction is switched to the RB sump (recirculation period). The time periods during which the RBS does not have thio-sulfate or hydroxide is conservatively estimated to be as long as
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21 minutes.
2.
For the two header case, the pH of the spray solution is between 10 and 11 for up to 1300 seconds (=22 minutes). For the one header case, precise pH valves are not available, but the estimated pH's seem to be slightly higher (a few tenths of a pH unit) than the two header case and the high pH condition seems to last about twice as long.
Analysis of thyroid dose increase as a. result of no chemical additives in the spray for this period resulted in very little effect.
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- Unusual Event Report No. 50-313/75-2 10.
Corrective Action:
Arkansas Power 6 Light company is reevaluating.the hydraulic study of Babcock 6 Wilcox and performing our own calculations. These results should be ready for submittal to the Commission by August 15, 1975.
Arkansas Power 6 Light Company has also notified all paint vendors to determine if those paints in the Reactor Building are compatible with a pil range of 11 to 12 (a' conservative range) for short periods of time (up to 45 minutes). Preliminary investigations of Babcock 6 Wilcox indicate that a short duration exposure in this range will not damage the coating systems. The results of AP6L's investigation will be reported to the Commission at the same time as hydraulic results are submitted.
Based on these results, further corrective ac' tion will be proposed and implemented if necessary.
11.
Failure Data:
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