ML20215F773
| ML20215F773 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 09/17/1986 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| CAL-86-07, CAL-86-7, NUDOCS 8610160370 | |
| Download: ML20215F773 (8) | |
Text
a PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 September 17, 1986 u.a.coonsv Docket Nos. 50-277 oC 6.U"P.O 50-278 vC T,0.
CLECTRIC PRODUCTIO. OEP ARTMENT Dr. T.
E. Murley, Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pa.
19406
SUBJECT:
Special Report:
Conditions of Non-Conformance with 10 CFR 50, Appendix R at Peach Bottom Atomic Power Station
REFERENCES:
1)
Fire Protection Safe Shutdown Report June, 1982 2)
Supplemental Information Alternative Shutdown Capability Assessment and Proposed Modifications, September 1983 3)
Confirmatory Action Letter 86-07 dated April 11, 1986 from S.
D.
Ebneter, NRC, to S.
L.
- Daltroff, PECo
Dear Dr. Murley:
NRC Confirmatory Action Letter 86-07 (reference
- 3) required PECo to submit a written report whenever a violation of 10 CFR 50, Appendix R, Section III G or J requirements has been identified during implementation of the confirmatory program.
A task force, presently conducting a fi.nal review of safe shutdown capability, has taken one generic change in approach to the safe and alternative shutdown capability, and identified four conditions of non-compliance with Appendix R requirements in Fire Area 02.
This Special Report describes these items and is submitted pursuant to the requirements of Confirmatory Action Letter 86-07.
O 8610160370 860917 gr b PDR ADOCK 05000277 II l
F PDR gg g7 1
F Dr. T.
E. Murlcy Srptcmber 17, 1986 Page 2 The task force is currently evaluating other potential conditions of non-compliance and is expected to complete this task this month.
A final report including the additional conditions of non-compliance with Appendix R,Section III G or J, will be submitted after the task force completes its review.
The Resident Inspector will be notified whenever additional conditions of non-compliance are confirmed by the task force.
GENERIC CHANGE IN APPROACH Description In both the safe shutdown and alternative shutdown submittals to the NRC, References 1 and 2, the Residual Heat Removal (RHR) System is assumed to operate in the shutdown cooling mode to provide long-term core cooling to achieve and maintain the cold shutdown condition.
However, the task force determined that a more efficient way to achieve and maintain cold shutdown is to use an alternate shutdown cooling method, following a postulated Appendix R fire.
Analysis has verified that an alternate shutdown cooling method can be achieved by supplying makeup water to the reactor pressure vessel using either one Core Spray pump or one RHR pump in the Low Pressure Coolant Injection (LPCI) mode.
Flow will return to the suppression pool through one or two of the safety relief valves.
Decay heat is removed from the containment in either of two ways: (1) dividing the flow of suppression pool water to the reactor pressure vessel and back to the suppression pool through the RHR heat exchangers, or (2) placing an RHR loop in the suppression pool cooling mode.
Early in the confirmatory program, the task force recognized that every effort should be made to:
(1) minimize the number of manual operations required of the plant operating staff to ensure adequate time for all required manual operations, and (2) comply with the existing Transient Respor.se Implementation Plan (TRIP) procedures in providing the plant operators with direction when normal shutdown procedures cotld not be used.
Although normal shutdown cooling is the preferred method, the rules for addressing Appendix R fires in some fire areas would put a significant burden on plant personnel to place the plant in normal shutdown cooling because numerous manual operations would be required.
Alternate shutdown cooling is the logical outcome of the TRIP procedures when normal shutdown cooling components are unavailable.
An enveloping analysis has been performed to verify that alternate shutdown cooling can be used as a long-term safe shutdown cooling method to achieve a cold shutdown condition (less than 212 degrees F and l
l
Dr. T.
E. Murley September 17, 1986 Page 3 reactor pressure between 50 and 150 psig) for an Appendix R postulated fire in any fire area.
The cold shutdown condition obtained differs slightly from that specified in the Technical Specifications since the reactor pressure vessel is not vented to containment.
Justification for Change in Approach The change in approach is justified because it: (1) minimizes the number of manual actuations the plant operating staff has to perform and (2) simplifies the plant procedures and ensures consistency with the logical outcome of the TRIP procedures.
Corrective Action No corrective action is required because the change in approach enhances the Appendix R verification.
CONDITIONS OF NON-COMPLIANCE IN FIRE AREA 02 CONDITION I Description Appendix R requires that, for each method, a train of safe shutdown components be identified that is free of fire damage for each plant fire area.
In Fire Area 02, the method of safe shutdown depends on the Core Spray System, in conjunction with the Automatic Depressurization System (ADS) and the RHR System in the suppression pool cooling mode.
To support operation of these systems, emergency ac power must be provided from Diesel Generator OAG12 and Diesel Generator OBG12.
Emergency Service Water (ESW) cooling will be provided by ESW Pump OAP57.
A flow path allowing discharge of the ESW cooling water must be provided through ESW Discharge Isolation Valve, MO-0498.
Control cables ZDOB5643B and ZDOB5643D for the ESW Discharge Isolation Valve MO-0498 are routed through Fire Area 02 (Room 262) and are not protected.
A hot short of either cable could cause Valve MO-0498 to close.
Significance of Condition Closure of the ESW Discharge Isolation Valve MO-0498 could cause the diesel generators to trip on high jacket water
Dr. T.
E. Murlcy September 17, 1986 Page 4 temperature or high lubricating oil temperature, unless a LOCA signal is present or the valve is opened within approximately 3 minutes.
Manual operation of the valve within 3 minutes is not possible.
Because this valve is located in the Emergency Diesel Generator Structure, it is not feasible to gain access to the valve and open it within 3 minutes.
Cause of Condition Reference 2 states that, for alternative shutdown,
" modifications that are to be made to the circuitry of ESW Valve 0498 will eliminate the need to confirm ESW valve alignment," and "the starter circuit of this motor-operated valve will be modified to preclude spurious closing as a result of hot shorts affecting the control circuit."
However, this condition resulted from a failure to recognize that a similar modification must be made to support safe shutdown as well as alternative shutdown.
Interim Corrective Actions An hourly fire watch was established on August 7, 1986 to assure early detection of a fire in Room 262 of Fire Area 02.
Permanent Corrective Actions Permanent corrective actions to comply with Appendix R,Section III G will be determined and implemented after the task force review is complete.
CONDITION II Description l
As discussed under Condition I, the method of shutdown in Fire Area 02 depends on the Core Spray System, in conjunction with the ADS.
Appendix R requires that sufficient diagnostic instrumentation survive the fire to allow operating personnel to ascertain the status of the required systems.
Among the parameters required for the Core Spray System is the flow measuring instrumentation provided in the core spray pump discharge line.
For Unit 3, Flow Indicator FI-3-14-50B is required as a diagnostic instrument for Core Spray flow.
F Dr.
T.
E. Murley September 17, 1986 Page 5 Cable 301243H is routed through Room 258 of Fire Area 02 and is not protected.
Failure of Cable 301243H could cause loss of flow indication from FI-3-14-50B.
Significance of Condition Fire damage to cable 301243H could cause loss of flow indication for the Core Spray System.
The loss of flow indication would not inhibit the operability of equipment needed for core cooling.
Cause of Condition Reference 2 states that as part of safe shutdown systems,
" flow-measuring instrumentation is provided in each core spray pump discharge line."
However, during the previous analysis it was not recognized that Cable 3Q1243H needed to be protected.
Interim Corrective Actions An hourly fire watch was established on August 7, 1986 to assure early detection of a fire in Room 258 of Fire Area 02.
Permanent Corrective Action Protecting or rerouting Cable 301243H is being investigated.
Permanent corrective actions to comply with Appendix R,Section III G will be determined and implemented after the task force review is complete.
CONDITION III Description As discussed under Condition I, the safe shutdown method used in Fire Area 02 requires Diesel Generator OAG12 and Diesel Generator OBG12 to support recovery.
Diesel Generator OAG12 requires long-term support from Station Battery 2AD01 which is charged by Battery Charger 2AD03.
Battery Charger 2AD03 receives power from Motor Control Center 20B59 which receives power from Emergency Load Center 20B10 through Cable ZA2B1014A.
Similarly, Diesel Generator OBG12 requires long-term support of Station Battery 3BD01 charged by Battery Charger 3BD03.
Battery Charger 3BD03
Dr. T.
E. Murley September 17, 1986 Page 6 receives power from Motor Control Center 30B60 which receives power from Emergency Load Center 30Bli through Cable ZB3 Bill 4A.
Cables ZA2B1014A and ZB3Blll4A are located in Fire Area 02 (Rooms 258 and 262) and are not protected.
Significance of Condition Fire damage to Cable ZA2B1014A and ZB3Blll4A could cause loss of power to Battery Chargers 2AD03 and 3BD03, respectively.
Once started, each diesel generator could continue to operate until depletion of the supporting station battery; however, long-term operation of Diesel Generators OAG12 and OBG12 requires that Station Batteries 2AD01 and 3BD01 be recharged.
Cause of Condition The reference 2 letter explained that repair procedures would be developed to ensure that adequate battery charging capability is established before the station batteries are exhausted.
The battery capacity calculations indicated that sufficient capacity existed to allow the unit to achieve cold shutdown for which repairs are permitted by Appendix R.
However, the calculations did not take into consideration multiple high impedance faults on the fire damaged associated circuits as specified in Generic Letter 86-10.
Inclusion of these faults in the calculations show that the batteries would be depleted during hot shutdown, for which repairs are not permitted by Appendix R.
Interim Corrective Action An hourly fire watch was established on August 7, 1986 to assure early detection of a fire in Rooms 258 and 262 of Fire Area 02.
[
Permanent Corrective Action l
Protecting or rerouting Cables ZA2B1014A and ZB3Blll4A is being investigated.
Permanent corrective actions to comply with Appendix R,Section III G will be determined and implemented after the task force review is complete.
l
Dr. T.
E. Murley Snptember 17, 1986 Page 7 CONDITION IV Description As discussed under Condition II, Appendix R requires that sufficient instrumentation survive a fire to provide operating personnel with the status of the plant and required systems.
For Unit 3, the instrumentation relied upon to survive an Appendix R fire is powered through Distribution Panels 30D23, 30Y33, 30Y34, and 30Y50.
Panels 30Y33, 30Y34, and 30Y50 are powered from Motor Control Centers 30B59, 30B60 and 30D08, respectively.
Panel 30Y50 can be powered from Motor Control Center 30B59 as well.
Panel 30D23 is powered from Station Battery 3CD01 which is charged by Battery Charger 3CD03 from either Motor Control Center 20B59 or 30B38.
As noted under Condition III, power could be lost to Motor Control Centers 20B59 and 30B60 because Cables ZA2B1014A and ZB3Bil14A are located in Fire Area 02 and are not protected.
Power could also be lost to Motor Control Center 30B59 because Cables ZA3A1505A and ZA3B1014A are in Fire Area 02 and are not protected.
Power could be lost to Motor Control Center 30B38 due to loss of Diesel Generator OCG12 and associated cables.
Power would initially be available to Motor Control Center 30D08 from Station Batteries 3BD01 and 3DD01, but would eventually be lost due to depletion of Station Batteries 3BD01, which is charged by Battery Charger 3BD03 from Motor Control Center 30B60, and Station Batteries 3DD01, which is charged by Battery Charger 3DD03 from Motor Control Center 30B39.
Power could be lost to Motor Control Center 30B39 due to loss of Diesel Generator ODG12 and associated cables.
Significance of Condition Loss of power to Motor Control Center 30B59 would result in the loss of drywell pressure process monitoring.
The other process parameters would be available on a short-term basis (approximately 3 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />) until the batteries supplying them became depleted due to the loss of battery charging feeds from Motor Control Centers 20B59, 30B38, 30B39 and 30860.
Cause of Condition Reference 2 identified three fire areas (02, 04 and 11) in the Radwaste Building.
Due to similar shutdown methodologies, Fire Areas 02 and 11 were combined into Fire Area 02 to limit the number of fire barriers that had to be
~
Dr. T.
E. Murley Septemb r 17, 1986 Page 8 upgraded.
During this consolidation the effect on instrumentation power supplies was overlooked.
Interim Corrective Action An hourly fire watch was established on August 7, 1986 to assure early detection of a fire in Rooms 258 and 262 of Fire Area 02.
Permanent Corrective Action As noted under Condition III, the protection of Cables ZA2B1014A and ZB3Bil14A is being investigated.
Protecting or rerouting Cables ZA3A1505A and ZA3B1014A is also being investigated.
Permanent corrective actions to comply with Appendix R,Section III G will be determined and implemented after the task force review is complete.
Previous Similar Occurrences Special Report dated May 22, 1986 from G. M Leitch, PECo, to T.
E. Murley, NRC, concerned conditions of non-compliance with Appendix R.
Ver tru y yours, Mfdf Attachments cc:
Mr.
D.
R. Muller, BWR Licensing, USNRC Mr. T.
P. Johnson, Resident Inspector, USNRC i
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