ML20198Q749
| ML20198Q749 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 06/02/1986 |
| From: | Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Butler W Office of Nuclear Reactor Regulation |
| References | |
| CON-#286-433 IEB-85-003, IEB-85-3, OL, NUDOCS 8606090358 | |
| Download: ML20198Q749 (3) | |
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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.19101 JOHNS.KEMPER VICE PRESIDENT
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June 2, 1986 Docket No. 50-352 Mr. W. R. Butler, Director BWR Project Directorate #4 U. S. Nuclear Regulatory Commission Washington, DC 20555
SUBJECT:
Limerick Generating Station, Unit 1 I.E.Bulletin 85-03
REFERENCE:
I.E. Bulletin No. 85-03 " Motor-Operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings" FILE:
GOVT 1-1 NRC (IEB-85-03)
Dear Mr. Butler:
I.E.Bulletin 85-03 described " Motor-Operated Valve (MOV) Common l
Mode Failures During Plant Transients Due to Improper Switch Settings".
This bulletin requested a response to Item a and the program and completion schedule for Items b through d.
As discussed below, Philadelphia Electric Company (PECo) is confident that Limerick I has been designed, constructed and tested in a manner which assures that the concerns discuased in the bulletin have been adequately addressed.
j Also as discussed below, we are participating in a BWROG committee on the subject Bulletin which will provide further confirmatory information in response to the Bulletin.
This response is in accordance with the conversation between D.
R. IIelwig, Philadciphia Electric Company (PECo), and R.11. Vollmer, NRC, 1&E on May 22, 1986. As discussed in that conversation, this response has been delayed beyond the original due date. We apologize for any inconvenience which may have been caused by this delay.
l As discussed in the BWROG letter to the NRC on this topic (J. M.
l Yulton (BWROG) to J. M. Taylor (NRC) dated April 29, 1986), the l
Bulletin requirements appear to be oriented towards PWR system characteristics. The design methods utilized for the M0V's at Limerick 1 are in essence identical to those employed by General Electric on over 30 operating BWR units.
8606090358 860602 PDR ADOCK 05000352 G
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. Further, Limerick 1 has been designed, constructed and tested under a quality assurance program which fully meets the requirements of 10CFR50, Appendix B.
This program, which has been imposed on both General Electric and our architect-engineer, provided controls which were applied to all phases of design, fabrication, installation and testing. The successful application of this program provides assurance of the adequacy of these activities.
PECo has substantial experience with the installation and maintenance of MOV's.
This experience has allowed us to knowledgeably perform a preliminary review of the two events described in the Bulletin. These two events both resulted from improper limit switch settings.
PECo recognized the importance of proper setting of limit switches at least as early as the construction checkout phase at Peach Bottom.
As a result, PECo conducted training programs for personnel involved in l
the setting of limit switches on motor operators as early as 1975.
These training programs have been integrated into the normal training of all personnel involved with the setting of limit switches on MOV's.
These programs continue to be reviewed and upgraded. These programs were all applied during the installation, testing and start-up of Limerick 1.
They continue to be applied as Limerick I operates.
l The following is a brief summary of the requirements for setting limit switches which are followed at PECo. The open limit switch is set such that the valve disc does not strike the back seat after opening electrically, precluding the type of failure experienced at Sequoyah 2.
The close limit switch is set such that the open torque switch is bypassed until after the valve disc is unseated, precluding the type of failure experienced at Davis-Besse.
Both these criteria are specifically stated in Maintenance procedures for Limerick 1.
Both open and close limit switches must be set empirically. The settings cannot be determined analytically due to variations in valve manufacturing tolerances and inertial effects. Limit switch setting procedures are specified in station procedure PMQ 500-0087 at Limerick.
We are working with the BWROC Committee to develop a scope of systems, range of events, and associated set of assumptions to assure a thorough and consistent reply to this Bulletin. The BWR00 Co=mittee is scheduled to complete its existing scope of work by September 1, 1986.
We plan to provide the PECo response within 60 days af ter NRC acceptance of the BWRCG Committee methodology addressing the concerns of I.E.Bulletin 85-03.
We trust that the additional information provided in this letter will be of assistance, pending the completion of the BWROG effort.
Sincerely, b{k i HDH/mb/05288601 Copy to:
See attached Service List
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cc: Troy B. Conner, Jr., Esq.
Ann P. Modgdon, Esq.
Mr. Frank R. Romano Mr. Robert L. Anthony Ms. Phyllis Zitzer Charles W. Elliot, Esq.
Barry M. Hartman, Esq.
Mr. Thomas Gerusky Director, Penna. Emergency Management Agency Angus R. Love, Esq.
Dnvid Wersan, Esq.
Robert J. Sugarman, Esq.
Kathryn S. Lewis, Esq.
Spence W. Perry, Esq.
Jay M. Gutierrez, Esq.
Atanic Safety & Licensing Appeal Board Atomic Safety & Licensing Board Panel Docket & Service Section Mr. E. M. Kelly Mr. Timothy R. S. Campbell 1
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