ML20211G169
| ML20211G169 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 02/11/1987 |
| From: | Carey J DUQUESNE LIGHT CO. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| 2NRC-7-028, 2NRC-7-28, 87-01, 87-1, NUDOCS 8702250301 | |
| Download: ML20211G169 (5) | |
Text
31 ce *CS
'Af 2NRC-7-023 2
Bewer Vall No. 2 Unit Project Organization P.O. Box 328 February 11, 1987 Shippingport, PA 15077 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 ATTENTION:
Dr. Thomas E. Murley Administrator
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Hot Pipe / Cable Clearance Potential Significant Deficiency Report 87-01 Gentlenen:
This Potentially Reportable Significant Deficiency Report is being submitted pursuant to the requirenents of 10CFR50.55(e).
It is anticipated that no additional reports will be required.
DUQUESNE LIGHT COMPANY By
- 3. 0/ Carey Sr. Vice President LMR/ ij r NRC/LMR/SUR/8701 Att ent AR cc: Mr. P. Tam, Project Manager (w/a)
Mr. J. M. Taylor, Director (3) (w/a)
Mr. J. Beall, Sr. Resident Inspector (w/a)
Ms. A. Asars, hRC Resident Inspector (w/a)
INPO Records Center (w/a)
NRC Document Control Desk (w/a) 8702250301 8702jj PDR ADOCK 05000412 3
-((:21
ATTACHMENT 1.
Summary Cable installation criteria did not adequately address the potential impact on cable anpacity and qualified life, resulting fran physical prox-imity to hot pipes.
2.
Immediate Action Taken Four fonnal calculations (12241-PH-140, PH-141, E-122 & E127) were gener-ated, approved and _ issued.
Mr. L. M. Rabenau, Canpliance Engineer, Beaver Valley Unit 2, notified Mr.
Dave Limroth, NRC Region I of this concern on January 12, 1987.
3.
Description of Deficiency Anbient tenperature is an important factor in cable sizing and in deter-mining the environnental qualification requirenents.
Since inadequate consideration was ghen to the increase in anbient tenperature caused by proximity to hot pipes, prenature failure due to accelerated thennal aging might have resulted.
4.
Analysis of Safety Implication Based on 2BVM-237 criteria, several clearance deviations have been identi-f i ed.
The case-by-case analysis that followed has resulted in assigning various degrees of rework to preclude the effects of elevated tenperature on cable due to proximity to hot pipes.
Solutions included:
1.
Installation of localized thermal pipe insulation 2.
Physical relocation of ' conduits 3.
Installation of heat shielding curtains Had these deficiencies not been identified, analyzed, and resolved, the safe operation and shutdown capability of the pl ant could have been adversely affected as illustrated by the following exanple:
Six conduits carrying safety-related cables, identified below, were installed in close proximity to a 38 in, exhaust pipe whose design tenperature is 1000*F.
Simil arly, clearance requirenents of the cable's counterparts belonging to the redundant safety train were vio-lated in the sane manner.
Heat shielding curtains were installed to keep the anbient tenperature around each group of conduits within tolerable limits with respect to the cables' ampacity and qualified life.
Had this situation not been resolved, simultaneous failures due to prenature-aging of the two redundant groups of Class 1E cables could have resulted.
This constitutes a conmon mode failure of redundant safety-related systens.
Affected cables are:
Orange, Cable Affected Eqpt Purple Cable Affected Eqpt 2HVDAOC512 2HVD*M0022A 2HV0BPC512 2HVD*M00228 (NOTE 1) 513 23A 513 23B (NOTE 1)
AOL005
- FN271A BPLOOS
- FN271B (NOTE 1)
A0K010
- FN222A BPK010
- FN2228 (NOTE 2) 2RMS40K501 25WS*RQIl00C 2RMS4PK503 25WS*RQIl00B 502 100A 502 1000 NOTE 1: Prenature cable aging could lead to functional failure of outdoor air danpers (*M0022A, B), return air danpers (*M0023A, B), and energency diesel roon ' exhaust f ans (*FN271A,B), thereby depriving both energency diesel generator roons of proper ventilation.
This situation could have prevented energency power generation necessary for safe shutdown capability during postulated accident conditions.
NOTE 2:
Fan *FN222A,8 operate 3 only during the diesel standby.
The failure of this fan will not affect functions of the safety related equipment.
Tenperature switches will alann in the control roon on high tenpera-ture in the diesel roon so appropriate action can be taken.
5.
Corrective Action to Resolve the Deficiency Four fonnal calculations (12241-PH-140, PH-141, E-122 and E127) were generated, approved and issued.
Using these calculations, it is possible to evaluate the impact of elevated anbient tenperatures, caused by proximity to hot surf aces, on cable anpacity and qualified life.
Based on these calculations, a field procedure entitiled:
" HOT PIPE CLEARANCE CRITERIA, 2BVM-237" was aeveloped.
The ensuing field walkdown resulted in identification of approximately 270 pipe / cable clearance violations.
Case-by-case analysis indicated that the majority of cases which could not be justified in accordance with Section 5.2 of 2BVM-237 required adding or i
upgrading thennal insulation of pipes. Only a few cases required physical rework (conduit relocation).
Where clearance deviations were identified, instructions to add or upgrade thennal insulation to hot pipes, or to reroute conduits were issued via E&DCRs.
New installations are governed by 2BVM-237 criteria.
o a
6.
Additional Report No additional reports are expected.
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