ML19260E264
| ML19260E264 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 01/08/1980 |
| From: | Pilant J NEBRASKA PUBLIC POWER DISTRICT |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| IEB-79-26, NUDOCS 8002140429 | |
| Download: ML19260E264 (2) | |
Text
bec to DAC:ADM:
CENTRAL FILES PDR:HQ LPDR
~
cooper NUCLEAR
~ "3 Nebraska Public Power District
"- " "*A*EO!'tM; NSIC j b STATE January 8, 1980 Mr. Karl V. Seyfrit, Director U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region IV 611 Ryan Pla::a Suite 1000 Arlingcon, Texas 76011
Subject:
Response to IE Bulletin No. 79-26
" Boron Loss from BWR Control Blades"
Dear Mr. Seyfrit:
This letter is written in response to the subject bulletin.
Nebraska Public Power District (NPPD)10 has a control rod history record system in existence which evaluates B depletion in the control blades at Cooper Nuclear Station (CNS).
Prior to the issuance of IE Bulletin No. 79-26, it had been (and still is), NPPD's polic to replace any con-1 trol blade prior to the attainment of 34 percent 3 depletion averaged over the upper one-fourth of the blade.
In actuality, no control blade is projected to exceed 50 percent B10 local depletion (25 percent B10 average depletion) prior to Fuel Cycle 7 (1981-1982 time frame); cur-rently CNS is approaching the end of Fuel Cycle 5.
Therefore, since NPPD already abides by the preferred action of IE Bulletin No. 79-26, it is our understanding that items 1 through 4 of the aforemertioned bulletin do not apply to CNS.
We will however, provide responses to items 1 through 5 of the subject bulletin for the purpose of further elucidation of NPPD's position on this issue; NPPD's responses are as follows:
1.
NPID has had in effect for some time a system to track control blade B10 depletion rates; these records are maintained on a con-tinuing basis.
2.
By use of a judicious control blade shuffling plan, no control 10 blade at CNS is expected to exceed 34 percent B average depletion prior to 1986.
80nS140 4 Z#/
Mr. Karl V. Seyfrit January 2,1980 Page 2.
Control blades will be replcced oc the beginning of the a.
cyc.le where they would be projected to attain 35 percent B10 average depletica; hence none with greater than 34 percent B10 cverage depletion will ever be in the CNS core.
b.
See respc~.se 2.a above.
3.
a.
As agreed in Washington during the Startup Physics Test meetf gs, CNS performs a control rod mobility and subcritical check to verify that the cote wi'l not go critical with the withdrawal of any one control rod.
b.
NPPD does not believc this iteu to apply to CNS as it is our policy to replace control blades before the 34 percent B10 average depletion value is axceeded, 4.
No control blades in the CNS core are projected to exceed 50 per-cent B10 local depletion (25 percent B10 average depletien) prior to 1981-1982.
Therefore, based upon that and the fact that control blades will be replaced before actaining 34 percent B10 cverage depletion, NPPD does not believe it necessary to destroy a control blade if it caa h9 avoided.
Also, it is NPPD's understanding that General Electric plans ta perform 1 destructive examination of 4 representative control blades selected from various operating placts.
Therefore, NPPD believes that the alternate criteria will be met.
5.
This letter connotes NPrD'a response to items 1 and 2.
Shutdown Margin Test results are filed as part of the plant surveillance records and os such are available for review by the NRC's Cooper IE Inspector; therefcre, NPPD does not see the rationale for a separate report.
It is expected that Ceneral Electric will file a generic report with the NRC for item 4 after the 4 representative control blades are examined.
If you have any questions regarding the enclosed information, please contact me.
Very truly yours,
. 'g 'M
.a
.. Pilant Director of Licensing and Ouality Assurance JMP: ROP:cg