ML19309D791
| ML19309D791 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco, Arkansas Nuclear |
| Issue date: | 01/28/1975 |
| From: | Cavanaugh W, Phillips J, Rueter D ARKANSAS POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML19309D781 | List: |
| References | |
| NUDOCS 8004110672 | |
| Download: ML19309D791 (3) | |
Text
.
m O
1.
Unusual Event Report No. 50-313/75-1 '
2.
Report Date:
1/28/75 3.
Occurrence Date:
1/14/75 4.
Facility:
Arkansas Nuclear One-Unit 1
.Russellville, Arkansas 5.
Identification of Occurrence:
Error in Babcock 6 Wilcox analysis of hot zero power ejected rod worth.
6.
Conditions Prior to Occurrence:,
N/A Steady-State Power Reactor Power MWth Hot Standby Net. Output MWe Cold Shutdown Percent of Full Power Refueling Shutdown Routine Startup
]
Operation Routine Shutdown Operation Load Changes During Routine Power Operation Other (Specify]
l 7.
Description of Occurrence:
On January 14, 1975, Babcock 6 Wilcox informed us of and forwarded.to us a report that was filed with the* Atomic Energy Commission on December 27, 1974, concerning Rancho Seco. The hot zero power ejected rod worth at Rancho Seco was found to exceed the 1.0% Ak/k Technical Specification limit.
In this report, it was noted that other operating B6W plants (in this case, Arkansas Nucicar One-Unit 1) contained the same calculational error but did not exceed the 1.0's Ak/k Technical Specification limit with the original control rod configuration. These plants may be affected following the control rod interchange at 250 Effective Full Power Days.
r r
t 8004110 M
July 5, 1974 NSP-10, Rev. O Page 1 of 3
m.
s
\\ul Unusual Event Report No. 50-313/75-1 4
8.
Designation of Apparent Cause of Occurrence:
Design X
Procedure Manufacture Unusual Service Condition Including Installation /
Environmental Construction Component Failure Operator Other (Specify) 9.
Analysis of Occurrence:
Re-analysis by B6W shows that the ejected rod worth is within the 1.0%
ak/k limit up to the control. rod interchange.. These analyses, however, show that the hot zero power ejected rod worth, with existing Technical Specification rod position limits, may exceed 1.0% ak/k after the control rod interchange. This interchange will take place after ANO-1 has a fuel exposure of 250 Effective Full Power Days.
- 10. Corrective Action:
Follow up analyses and reports will be studied to determine if this efected rod worth will indeed exceed 1.0% ak/k.
Technical Specification revisions will be provided in a timely manner prior to control rod interchange, if analysis proves,this to be necessa ry.
/"
V July 5, 1974 NSP-1D, Rev. O Page 2 of 3
Unusual Event Report No. 50-313/75-1
- 11. Failure Data:
N/A 12.
Reviews and Approvals:
Reviewed and Approved by:
Plant Safety Committee Yes ( )
No QC )
Plant Superintendent Yes ( )
No (K )
O
Reference:
Not required Date:
Reviewed by:
%m Date:
/ 3/ 7d'
/ Licensing'Supdrvis' o,r
{
Approved by: t
[/[y,'.:
[yr
/'
Date: #- V- ) \\ '
./
afet Review 1 tee i
[
Approved by:
- ^ r ' '
Date: / J/ 7[
Manager of Nu I dr Services
/
Approved by: ( )@f/',' fj.'
' r/,fr.d Date: [
V-d5' Director of P wer P'oduction r
Approved by:
7/'/'-(
i f
. e --
Date: 7 T-Senior Vice President O
July S, 1974 NSP-10, Rev. O Page 3 of 3
. -.