ML20237D016

Forwards Response to RAI Re USI A-46 for Seismic Adequacy of Mechanical & Electrical Equipment

ML20237D016
Person / Time
Site:	Peach Bottom
Issue date:	08/17/1998
From:	Geoffrey Edwards PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR NUDOCS 9808240308
Download: ML20237D016 (7)

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e-e ct"_ tion Support Department ES!m.

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v PECO NUCLEAR-ecco eeerov comne,v 965 Chestertxook Boulevard j

A Unit of PECO Energy wayne. PA 19087-5691 I

August 17,1998 Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 i

U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 I

Subject:

Peach Bottom Atomic Power Station, Units 2 and 3 Response to Request for Additional Information Regarding Unresolved Safety issue (USI) A-46; Seismic Adequacy of Mechanical and Electrical Equipment

Reference:

Letter from Mohan C. Thadani, U.S. Nuclear Regulatory Commission (USNRC), to Garrett D. Edwards, PECO Energy Company,.

l dated June 18,1998 i

i Dear Sir.

j Your request for additional information (RAI) which was transmitted by the reference letter requested a response within 60 days. Attached is our response to your RAl.

- to this letter provides a restatement of the questions, followed by our response.

if you have any questions, please contact us.

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Very truly yours,

=k arrett D. Edwards Director-Licensing Enclosure. Affidavit, Attachment 1 i

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cc:

H. J Miller, Administrator, Region I, USNRC

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I A. C. McMurtray, USNRC Senior Resident inspector, PBAPS

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9908240308 980817 PDR ADOCK 05000277 P

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I COMMONWEALTH OF PENNSYLVANIA :

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COUNTY OF YORK J.' Doering, Jr., being first duly sworn, deposes and says:

1 That he is Vice President of PECO Energy Company, the Applicant herein; that he has read the enclosed response to the NRC request for additional information concerning Unresolved Safety Issue A-46, and knows the contents thereof; and that the statements and i

- matters set forth therein are true and correct to the best of his knowledge, information and belief.

/]

Vice President [

Subscribed and sworn to before me this /3 day of August 1998.

922 b 146tary Public

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i NOTARIALSEAL JANETL WILEY,NOTARf PUBUC PEACH BOTTOM TWP., YORK c0UNTY, M wcoutsesON EPIRESJUNE U,2002 L___..__

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l ATTACHMENT 1 t

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1 Dochet Nos. 50-277 50-278 l

License Nos. DPR-44 l

DPR-56 Response to Request for Additional Information l

Peach Bottom Atomic Power Station, Units 2 and 3 l

Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors Question 1:

Describe what reviews were performed to determine if any local operator actions required to safely shut down the reactor (i.e., implement the SSEL (safe shutdown equipment list)) could be affected by potentially adverse environmental conditions (such as loss of lighting, i

excessive heat or humidity, or in-plant barriers) resulting from the seismic event. Describe how staffing was evaluated and describe the reviews that were conducted to ensure operators had adequate time and resources to respond to such events.

Response 1:

As described in Generic implementation Procedure, Revision 2, (GlP-2), Part II, section 3.2.5, the only potential events which must be considered in the Unresolved Safety Issue (USI) A-46 program are a safe shutdown earthquake (SSE) and loss of offsite power (LOOP). The plant operating procedures used to shut down the plant following a LOOP have previously been validated for local operator actions as one of the Updated Final Safety l

- Analysis Report Chapter 14 events. This includes potentially adverse environmental conditions such as loss of lighting and excessive heat and humidity. Note that the USl A-46 l

accident scenario (SSE + LOOP) explicitly excludes loss of coolant accidents (LOCA) and l

high energy line breaks (HELB). Therefore, the heat and humidity conditions in the plant are postulated to be equivalent to those following a LOOP.

The potential for failure of plant structures and equipment is not considered credible at eastern earthquake levels. Earthquake experience has shown that typical industrial structures are able to withstand earthquakes larger than SSEs for eastern U.S. nuclear plants without collapse or failure. The potential for local failure of architectural features (such as suspended ceilings in the control room) and the potential for adverse seismic spatial interactions in the vicinity of safe shutdown equipment, where local operator actions l

may be required, was explicitly evaluated as required in GlP-2 Part 11, section 4.5 and Appendix D. For example, this review included a check that the masonry walls near safe shutdown equipment were seismically adequate based on results of the IE Bulletin 80-11,

" Masonry Wall Design," program.

The systems and equipment selected for seismic review in the USl A-46 program are those used in the normal, abnormal and emergency operating procedures to bring the reactor from a normal operating state to a safe shutdown condition. As required by GIP-2 Part II, sections 3.2.8 and 3.7 and as shown in section 4.3 of the safe shutdown equipment list (SSEL) report, the SSEL was reviewed by PBAPS Operations to confirm that it is compatible with these plant procedures. Since these procedures have already been validated to ensure that adequate time and resources are available for operators to respond to a LOOP, it was not necessary to re-validate these procedures for the USl A-46 program. No specific actions beyond those for the LOOP are required for the SSE except investigation of potential damage to rotating equipment, diesel fire systems and large tanks. Most of these actions may be performed by non-operations personnel and therefore do not affect operator actions to safely shutdown the plant.

Docket Nos 50-277 50-278 License Nos. DPR-44 DPR-56 Question 2:

j As part of the licensee's review, were any control room structures that could impact the operator's ability to respond to the seismic event identified? Such items might include, but are not limited to: MCR ceiling tiles, non-bolted cabinets, and non-restrained pieces of equipment (i.e., computer keyboards, monitors, stands, printers, etc.). Describe how each of these potential sources of interactions has been evaluated and describe the schedule for implementation of the final resolutions.

Response 2:

Control room structures and other items located in the control room that could impact the operator's ability to respond to a safe shutdown earthquake include the control room suspended ceiling, unsecured control room furniture such as lockers, tables, and waste barrels. These structures and components were evaluated as part of Peach Bottom's A-46 review.

The method used for evaluating these potential sources of spatial interaction is described in Generic Implementation Procedure, Revision 2, (GIP-2), Part II, Section 4.5 and Appendix D.

After performing this review we concluded that all of the structural items passed the GIP-2 i

screening criteria. However several housekeeping issues associated with unsecured items l

were identified in the control room as outliers. Table 4.2-4 identified several control room i

cabinets that are being tracked as outliers until the housekeeping issues are resolved. The particuiu items that were identified on the screening evaluation work sheets (SEWS) are:

An unsecured locker in the vicinity of cabinet 00C29A,B,C and D.

Aperture card cabinet files and readers located at the rear of cabinet 30C124.

Waste barrels / containers, a coat rack and a small table on rollers were located in the vicinity of cabinet 20C124 These specific issues, identified above, have been corrected, an J procedural controls are in the process of being implemented to control the location of items that can be potential sources of seismic interactions.

Our letter of May 7,1996 which transmitted the summary report for resolution of USl A-46 committed us to resolve all outliers by December 31,2000. This includes the full implementation of the procedural controls described above and the resolution of all housekeeping related outliers.

Question 3:

Describe what reviews were performed to determine if any local operator actions were required to reposition " bad actor relays." For any such activities, describe how adverse environmental conditions (such as loss of lighting, excessive heat or humidity, or in-plant barriers) resulting from the seismic event were analyzed and dispositioned. Describe how staffing was evaluated and describe the reviews that were conducted to ensure operators had adequate time and resources to respond to such events.

Response 3:

The term " bad actor relays" refers to the list of relays in Appendix E of EPRI Report NP-7148. These relays have low seismic ruggedness or demonstrated sensitivity to high frequency vibration. The term used in EPRI NP-7148 characterizes these relays as " low f

ruggedness" relays.

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'A Docket Nos. 50-277 50-278 License Nos. DPR-44 i

l DPR-56 A review of relays listed in Appendix E of EPRI Report NP-7148 and relays in operation at Peach Bottom Atomic Power Station (PBAPS) was performed. There are two models on this list that are in service at PBAPS. One relay is a Westinghouse Model Number SV1876294.

A functional relay evaluation of the operation of this relay in all applications at PBAPS was l

performed. This evaluation determined that relay (contact) chatter is acceptable for this model relay at PBAPS.

The other relay is a GE Model Number 12PVD11C11 A. Our letter of May 7,1996 which transmitted the summary report for resolution of USl A-46 committed us to replace all of these relays with seismically qualified relays by December 31,2000.

Based on the planned replacement of the GE

• bad actor relays" and the evaluation performed on the Westinghouse relays, no additional evaluations are required to determine if local operator actions are needed to reposition " bad actor relays."

Question 4:

Describe which of the operator actions associated with resetting SSEL equipment affected i

by postulated relay chatter are considered to be routine and consistent with the skill of the craft. If not considered skill of the craft, what training and operational aids were developed to ensure the operators will perform the actions required to reset affected equipment?

Response 4:

Resetting equipment that may be actuated as a result of a safe shutdown earthquake is consistent with the skill and training required of our operato s. Resetting this equipment is an activity which is included in the scope of expected operator actions contained within our normal, abnormal and emergency operating procedures.

Question 5:

l Assume the alarms associated with " bad actor relays" are expected to annunciate during the l

seismic event. Do the operators have to respond to those annunciators and review the l

annunciator response procedures associated with them for potential action? How would those additional actions impact the operators' ability to implement the Normal, Abnormal, i

and Emergency Operating Procedures required to place the reactor in a safe shutdown condition?

Response 5:

An evaluation of the operation of the Westinghouse Model Number SV1876294 " bad actor relay"(see response to Question 3) was performed. This evaluation indicates that chatter of these contacts is acceptable and a mis-operation of the control circuit will not occur. No additional operator actions are required.

The replacement of the GE Model Number 12PVD11C11 A " bad actor relay" (see response to Question 3) identified at PBAPS assures that there will be no additional alarms associated with " bad actor relays." Based on the replacement of this " bad actor relay," no additional evaluations regarding operator response to annunciators associated with this equipment is required.

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Docket Nos. 50-277 50-278 License Nos. DPR-44 DPR-56 l

Question 6:

To the extent that Normal, Abnormal, and Emergency Operating Procedures were modified l

to provide plant staff with additional guidance on mitigating the A-46 Seismic Event, describe what training was required and provided to the licensed operators, non-licensed operators, I

and other plant staff required to respond to such events.

Response 6:

As discussed in Section 4.3 of Attachment 1 to PECO Energy Company letter to NRC dated

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May 7,1996, PBAPS operations reviewed the Safe Shutdown Equipment List (SSEL). They i

determined that with the equipment on the SSEL and using plant normal and emergency procedures, operators could bring the plant to a safe shutdown condition. No Normal, Abnormal or Emergency Operating Procedures were required to be modified to mitigate the A-46 Seismic Event. Also, the resolution of outliers does not require any new operating procedures or revisions to existing operating procedures. Therefore, no additional training was required to be provided to operators or other plant staff to respond to the A-46 Seismic Event.

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