ML20096F591
| ML20096F591 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 08/08/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8409100140 | |
| Download: ML20096F591 (2) | |
Text
.
4 s
.,..- m -
.p. ~*-
'i
-TENNESSEE VALLEY AUTHORITY JHATTANOOGA. TENNESSEE 374ot 400 Chestnut Street Tower II-n
- 84) AljG 14 P lAbg3$ 8,1984 BLRD-50-438/84-03 BLRD-50-439/84-03
- c s
U.S. Nuclear Regulatory Commission i-Region II-
' Attn:
,Mr. James'P. 'O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Mr. O'Reilly:
.BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - TIME SPAN FOR TEMPERATURE: SWITCH
. RESPONSE - BLRD-50-438/84-03, BLRD-50-439/84 SECOND INTERIM REPORT-The subject deficiency was initially reported to NRC-0IE Inspector C. A. Julian on December 27, 1983 in accordance-with 10 CFR 50.55(e) as NCR BLN BLP 8334. This was followed by our interim report dated January 25, J
1984. Enclosed is our second interim report. We expect to submit our next report by June 4,1985.
If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.-
_ ~
. Very truly yours, TENNESSEE VALLEY AUTHORITY
+
L*
e L. M. Mills, Manager Nuclear Licensing
-Enclosure cc:
Mr. Richard C. DeYoung, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nucleaa Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia. 30339 8409100140 840808 PDR ADOCK 05000438 S
PDR 9
OFFICIAL COPY An Equal Opportunity Employer '
ll M
\\
w _ e.w ENCLOSURE l
\\
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 TIME SPAN FOR TEMPERATURE SWITCH RESPONSE BLRD-50-438/84-03, BLRD-50-439/84-03 NCR BLN BLP 8334 10 CFR 50.55(e)
SECOND INTERIM REPORT Description of Deficiency Automatic Switch Company ( ASCO) ambient monitoring temperature switches OSA-ITS-609A-A through 609D-A, 265A-A, 265B-A, 266A-B, 266B-B, and 601 A-B
~
through 601D-B were procured to detect and initiate isolation of pipe breaks in the auxiliary steam system which is located throughout the Auxiliary Building common zone.
Due to the slow response to these switches, they are incapable of detecting rapid temperature changes, and therefore, do not initiate steam line isolation rapidly enough to limit the ambient temperature to an acceptable level for use in qualifying safety-grade electrical equipment. Additionally, it has been found that the switches themselves are not environmentally qualified to operate in the anticipated accident environment. The existing analysis to determine the environmental response of the common zone due to postulated pipe breaks in the system was performed before procurement of the switches and was based upon incorrect switch response daaracteristics. An analysis using the correct switch response characteristics predicts environmental temperatures which are in excess of the qualification temperature of the affected safety-related equipment.
Interim Progress Procurement and detection system redesign efforts are underway to replace the ASCO switches with fast-acting, environmentally qualified Fenwal model 18023-7 temperature switches. The steam line break accident environmental profile will'be re-evaluated based on the operating ch'aracteristics of the new switch. The environmental drawings and equipment qualification efforts will be revised to reflect those new environmental conditions.
m e
-