ML20137C353
| ML20137C353 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom, Limerick  |
| Issue date: | 03/14/1997 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-96-05, GL-96-5, NUDOCS 9703240229 | |
| Download: ML20137C353 (9) | |
Text
_ _ _ _ _
Etition suppoet Department GL 96-05
..m.__
v PECO NUCLEAR nm emo c-v 965 Chesterbrook Boulevard
'A Unit of PECO Energy Wayne, PA 19087-5691 i
j March 14,1997
'l Docket Nos. 50-277 j
a 50-278 i
l 50-352 50-353 License Nos. DPR-44 DPR-56 NPF-39 4
NPF-85 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 1
i
SUBJECT:
Peach Bottom Atomic Power Station, Units 2 and 3 Limerick Generating Station, Units 1 and 2 i
Response to Generic Letter 96-05,
- Periodic Verification of Design-Bases Capability of Safety-Related Motor-Operated Valves" 7
2
References:
1)
Letter from D. R. Helwig (PECO Energy Company) to U. S. Nuclear
)
Regulatory Commission (USNRC) dated December 28,1989 j
2)
Letter from D. R. Helwig (PECO Energy Company) to USNRC dated March 16,1992 i
1 3)
Letter from G. A. Hunger Jr.(PECO Energy Company) to USNRC dated April 14,1994 4)
Letter from G. A. Hunger Jr. (PECO Energy Company) to USNRC dated December 21,1994 5)
Letter from G. A. Hunger Jr. (PECO Energy Company) to USNRC dated June 16,1995 6)
Letter from G. A. Hunger Jr. (PECO Energy Company) to USNRC dated August 2,1995 7)
Letter from G. A. Hunger Jr. (PECO Energy Company) to USNRC dated December 29,1995 l
8)
Letter from G. A. Hunger Jr. (PECO Energy Company) to USNRC dated t
November 151996
Dear Sir:
Attached is our response in accordance with Required Response 2 to Generic Letter (GL) 96-05
)
dated September 18,1996. GL 96-05 concems the periodic verification of design basis i
capability of safety-related motor-operated valves.
8 b
9703240229 970314 "
PDR ADOCK 05000277?
P.
PDR R 24oogg is,spappupppu
Page 2 1
4 If you have any questions, please contact us
. Very truly youm, Y
l D
W' G. A. Hunger Jr.
Director-Licensing Attachments cc:
H. J. Miller, Administrator Region I, USNRC (w/ attachment)
W. L Schmidt, USNRC Senior Resident inspector, PBAPS (w/ attachment)
N. S. Perry, USNRC Senior Resident inspector, LGS (w/ attachment) i l
1 l
i
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=.
.. ~ -.. -
GL 96-05 bec:
W. T. Henrick, Public Service Electric & Gas R.1. McClean, State of Maryland J. A. Isabella, Atlantic Energy A. F. Kirby, Ill, Delmarva Power & Light Company R. R. Janati, Commonwealth of Pennsylvania D. M. Smith - 63C-3 G. R. Rainey - 63C-3 D. B. Fetters - 62C-3 W. G. MacFariand IV-LGS, SMB1-1 T. N. Mitchell - PB, SMB4-9 G. D. Edwards - PB, A4-1S R. W. Boyce - LGS, GML5-1 M. E. Wamer - PB, SMB3-2A E. F Sproat - LGS, SSB 3-1 J. B. Cotton - 63B-1 G. A. Hunger.- 62A-1 T. J. Niessen - 63C-3 R. A. Kankus - 63C-5 G. J. Lengyel - PB, A4-SS J. L. Kantner - LGS, SSB2-4 M. A. Christinziano - 62A-1 D. P. Helker - 62A-1 i
PBAPS ISEG - PB, SMB4-6 PA DEP BRP inspector - LGS, SSB2-4 Commitment Coordinator-62A-1 Correspondence Control Desk-61B-3 DAC - 61 B-5 i
1
d AFFIDAVIT COMMONWEALTH OF PENNSYLVANIA
- ss COUNTY OF CHESTER l
D. B. Fetters, being duly sworn according to law, deposes and says:
That he is Vice President of PECO Energy Company; that he has read the enclosed response to Generic Letter 96-05 dated March 14,1997, for Peach Bottom facility i
i Operating Licenses DPR-44 and DPR-56 and Limerick Operating Licenses NPF-39 and NPF-85, and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
i I
_W
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1 Vice President i
a l
Subscribed and Sw n to before me this /
ay of March,1997.
gtary Public a
i e, b 5 $ fif*( m 4
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GL 90-05 RESPONSE TO GENERIC LETTER 96-05 PEACH BOTTOM ATOMIC POWER STATION LIMERICK GENERATING STATION REQUIRED RESPONSE:
- 2. Within 180 days from the date of this Generic Letter.
(a)
A written summary description of its MOV periodic verification program established in accordance with the Requested Actions Paragraph.
RESPONSE
4 The PECO Energy program for periodic verification of design basis capability of motor-operated valves (MOVs) at Peach Bottom Atomic Power Station (PBAPS) and Limerick Generating Station (LGS) is documented in PECO Energy Specification NE-145. The program provides for graded test intervals based on MOV safety significance and demonstrated performance margin.
PECO Energy has reviewed this program and, after careful consideration of on-going industry developments with component inservice test methods, decided to develop a revised program for MOV periodic verification. The following paragraphs discuss:
1.
the acceptability of the current program during the revised program implementation interval, and i
ll. the revised program being developed and an estimated schedule forimplementation of the revised program.
l.
CURRENT (INTERIM) PROGRAM ACCEPTABILITY The current PECO Energy program for MOV periodic verification as documented in PECO Energy Specification NE-145 will be used as the JOG interim periodic verification test program.
The program is based on static diagnostic MOV tests at graded test intervals based on MOV safety significance and demonstrated performance margin as described below. The current program discussed in this response is dynamic by nature and, while the discussion of the specifics provides an accurate description of the present state of each, PECO Energy may continue to revise the program in accordance with the approved revision processes and the applicable regulatory requirements, without modification of this response.
The periodic verification test (PVT) frequency range for each MOV is determined by coupling the MOV relative importance to plant safety via its Probabilistic Safety Assessment (PSA) and/or Operational importance Rank with the Minimum As-left Thrust / Torque Margin. Eight other MOV attributes are evaluated to determine a PVT score which is used to select a specific MOV PVT frequency associated with refueling cycles ( R ), within the range established above. The standard MOV PVT frequencies are set as follows:
1
GL 96-05 l
1
]
PSA and/or Operations Test %uendes i
importance Rank Thrust /
PVT PSA OPS PV Test Exercise Post Maintenance Test M
High N/A and
<10%
Not Used 1R IST Static and/or Dynamic High N/A or.
<5%
265 1R IST Diagnostic High N/A or
<5%
>0; <65 2R IST j
Medium or 6 to 10 or
<15%
255 3R IST Static and/or Dynamic l
Medium or 6 to 10
.or
<15%
>0; <55 4R IST Diagnostic I
Low or 3 to 5 or
<30%
250 SR IST Low or 3 to 5 or
<30%
240; <50 6R IST Static and/or Dynamic l
l Low or 3 to 5 or
<30%
220; <40 7R IST Diagnostic i
Low or 2 to 5 or
<30%
>0; <20 8R IST l
t j
None 3 to 10 -
and 2100 %
Not Used 8R IST Low-Low and 1 to 2 and 230 %
Not Used N/A IST Static and/or Dynamic 4
None and 1 to 2 and 230 %
Not Used N/A IST Diagnostic l
4 l
The current PECO Energy periodic test progrsm is acceptable until the revised program is implemented for many reasons. Among these reasons are:
4 i
1.
MOV design basis capability was demonstrated by conservative, bounding performance j
parameters and in-situ test setup.
a)
MOV Program setup criteria accounts for degradation mechanisms including 3
l lubrication degradation, degraded voltage, and elevated temperature.
l b)
MOV Program setup criteria based on bounding valve factors which account for
]
aging, conservative rate of loading (ROL) or load sensitive behavior effects, and an additional Engineering Safety Factor (ESF).
]
c)
Periodic testing performed on staggered intervals per MOV family.
2.
The current program is implemented on a graded approach based on MOV safety significance where emphasis is placed on High safety significant and low margin MOVs.
' Safety significance is based on the combined consideration of risk-significance and MOV performance margin resulting in lower margin MOVs classified as higher safety significance independent of PSA risk significance, a)
Current safety significance ranking consistent with and more conservative than
' latest industry guidance, b)
The PECO Energy categorization of MOVs identified as PSA High and PSA Medium with low (<5%) margin are consistent with the ASME/NRC HSSC criteria and are diagnostically tested on an interval 53R. PSA Medium MOVs with higher margin would be diagnostically tested on an interval 54R. This is more frequent testing than recommended by the JOG Interim Periodic j
Verification Test Program for high and medium risk MOVs.
2 i
GL 96-05 c)
The Low and Low-Low safety significant MOVs were selected based on criteria more conservative than the ASME/NRC LSSC criteria and are tested on an interval >5R. The Low and Low-Low selection criteria requires that the MOVs have significant performance margin. Many of these MOVs repeatedly demonstrate design basis capability during routine plant operation and many 4
have low design basis differential pressure and flow service conditions similar to static test conditions.
j-d)
Selection of current test intervals includes criteria for operational importance, j
Thrust Margin, Accident Environment, Normal Environment, Process Service i
Conditions, Normal Function, Accident Function, Stroke Frequency, Limiting Thrust, and History.
3.
The current program does not include certain MOVs assumed capable of retuming to t
their safety position when infrequently or for short periods of time placed in a position that prevents their safety system or train from perfomling its safety function. Many of these MOVs repeatedly demonstrate design basis capability during routine plant operation and many have low design basis differential pressure and flow service conditions similar to static test conditions.
4.
Additional Defense in Depth is provided though:
a)
Tracking & Trending program, b)
MOV self-assessment, monitoring and cognizance of industry activities, c)
Post Maintenance test - matrix requires rebaseline testing including a mix of static and dynamic diagnostic testing, d)
Maintenance-Rule performance monitoring, e)
IST Program requires frequent exercising and performance monitoring, and f)
Non GL89-10 MOVs assumed capable of retuming to their safety position are demonstrated capable during frequent system performance tests.
- 11. REVISED PROGRAM DESCRIPTION PECO Energy has been participating actively in American Society of Mechanical Engineers (ASME) activities associated with risk-informed performance-based Inservice Testing (IST) for many years. The revised program for periodic verification of design basis capabliity of MOVs at PBAPS and LGS will be developed and implemented in accordance with formal ASME and NRC requirements and guidelines when completed.
PECO Energy is also participating in the Joint Owners' Group (JOG) Periodic Verification (GL 96-05) Program. This participation includes dynamic testing of MOVs assigned by the JOG,
)
periodic review of the current PECO Energy periodic verification test program based on JOG recommendations, and consideration of issues raised in the NRC Safety Assessment cf the JOG program.
Scope The scope of the MOV periodic verification program will include those MOVs that are required to perform their active safety function consistent with the current licensing bases of Peach Bottom and Limerick plants.
3
___-.__m._..
GL g6-05
.~
, Safety-Significance Categorization The MOV penodic verification program will include a safety significance categorization of MOVs that will guide program implementation. The safety-significance categorization will be based on plant specific Probabilistic Safety Assessment (PSA) risk rankings, deterministic considerations including MOV performance margins and the current licensing basis integrated with an expert panel process. The safety-significance categclization will group MOV's as High Safety Significant Components (HSSCs) and Low Safety Significant Components (LSSCs). This categorization will be performed and documented consistent with ASME and NRC prepared and/or endorsed guidance documents Test Strategies The MOV periodic verification program will include different periodic verification test strategies 3
for the HSSCs and LSSCs. Test strategy includes both test methodology and test frequency.
I The test strategies will include an appropriate mix of static and dynamic MOV testing and will also include periodic MOV exercising.
The HSSC test strategy will identify and detect precursors to failure and trend degradation that could lead to failure. The HSSC test interval will be selected based on observed performance so that the next test is performed prior to MOV degradation below an established margin of safety.
1 In the absence of supporting performance data, the HSSC test interval wi!! be no greater than 3 1
refueling cycles.
The LSSC test strategy will verify that the MOV is not in a failed state and will be performed such that MOV capability is assured. In the absence of supporting performance data, the LSSC test interval will be no greater than 3 refueling cycles, it is important to note here that PECO Energy does not intend to allow for any MOVs within this periodic verification program to "run-to-failure."
J Program implementation The revised MOV periodic verification program will be developed and implemented on a schedule dependent on specific industry and PECO Energy activities. Industry activities affecting program development include completion of the JOG Periodic Verification Program, ASME Code and NRC guidance documents.
- JOG Periodic Verification Program documents, which are currently scheduled for completion early in calendar year 2002, include the following:
1.
BWR Owners' Group Program on Motor-Operated Valve (MOV) Periodic Verification, NEDC-32719, March,1997 (JOG Topical Report).
' 2.
BWR Owners' Group Final Periodic Verification Program Criteria Topical Report.
3.
NRC Safety Assessment / Regulatory Guide on Periodic Verification Topical Reports.
- ASME Code and NRC Regulatory Guide documents are currently scheduled for publication the end of calendar year 1997 and include the following:
- 1. ASME Code Case OMN-x; Requirements for Safety Signi6cance Categorization of Components Using Risk Insights for Inservice Testing of LWR Power Plants.
2.
Potential new code case for MOV inservice testing to support OMN-x or revision to 1
ASME OMN-1; AMemative Rules 16r Preservice andInservice Testing of Certain Electric A00 tor-Operated Valve Assemblies in Light-Water Reactor Power Plants.
4 i
GL 96-05 i
3.
N.RC Regulatory Guide for Risk-informed Inservice Testing.
4 4.
NRC Standard Review Plan Risk-Informed inservice Testing.
5.
Revision to 10 CFR 50.55a; Codes and standards.
PECO Energy activities required to implement the revised program include Engineering Specification and Plant Procedure revisions which will be completed 12 months after publication l
of the final ASME and NRC guidance.
PECO Energy expects to have the revised MOV periodic verification program developed and ready for implementation in early 1999. The program will be periodically reviewed as feedback from the JOG Periodic Verification Program is received. A program implementation Schedule is shown below; i
1 Year 1 l Year 2 l Year 3 l Year 4 l Year 5 l Year 8 j
10 Task Name 1907 1998 199G 2000 2001 2002 1
PECO Energy interim PV Program q
2 Irterim Static Test Program Current Program 3
Dynamic MOV Tests for JOG PV Program 4
ASME Code Cases q
5 Develop & Approve Comp. Safety Categorization Code Case
(
8 Develop / Revise / Approve MOV Specific IST Code Case 7
NRc Rl4sT Regulatory Guidance qp Ilp 8
Develop / Publish RI-IST Reg Guide (s) ll.
9 Develop / Publish RI-IST SRP Section(s)
.g 10 Endorse ASME Code Cases
[
12 PV Topical Report
/17; 13 NRC Safety Evaluation l
14 Dynamic Test Program l
15 PV Final Criteria Topical Report 18 NRC Safety Evaluation Supplement 5
ji7 PEco Energy Efforts g
l l
I
,7 Review Program Scope Re CLB lg is Rev6se MOV Program Specifications 20 Revise PBAPS & LGS Procedures i
21 incorporate CLB Review & JOG PV Program 22 Final PECO Energy MOV PV Program h
5