ML20133E313
| ML20133E313 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/08/1997 |
| From: | Nunn D SOUTHERN CALIFORNIA EDISON CO. |
| To: | Collins S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| NUDOCS 9701130003 | |
| Download: ML20133E313 (13) | |
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,}e EDISON
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SOUDIERN CAufORNIA l
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An EDISON INTERNATIONAL Company January 8,1997 Mr. S. J. Collins i
Deputy Regional Administrator U.S. Nuclear Regulatory Commission Region IV l
Suite 400,611 Ryan Plaza Arlington, Texas 76011-8064 l
Dear Mr. Collins:
Subject:
Request for Additional Information - Maintenance Rule implementation San Onofre Nuclear Generating Station, Units 2 and 3
References:
(1)
Letter, G. T. Gibson (Edison) to T. P. Gwynn (USNRC:RIV), " San Onofre Nuclear Generating Station's (SONGS) Response to NRC Inspectors Follow-up on Unresolved item (50-361(362)/96009-03)",
i dated October 31,1996 (2)
NRC Inspection Report 50-361/96-14 and 50-362/96-14, dated December 10,1996 On January 3,1997, Mr. Harold B. Ray, Executive Vice President, I and other Senior Management of the San Onofre Nuclear Generating Station, met with you and members of your staff and members of the Division of Nuclear Reactor Regulation, to discuss our implementation of 10 CFR 50.65, " Requirements for monitoring the effectiveness of maintenance at nuclear power plants". During that meeting, I committed to providing you with a letter which would: (a) delineate which Systems, Structures, or Components (SSCs) could not have been moved from (a)(1) using the guidance of the Nuclear Energy Institute (NEI) (Enclosure 1); and, (b) provide specific responses to questions raised during our meeting (Enclosure 2).
In Reference 1, we provided our initial response regarding our implementation of the Maintenance Rule based on the October 25,1996 NRC Pre-Exit interview for the Reference 2 inspection. In our January 3,1997 meeting, we reviewed Edison's efforts (k
to prepare for and implement the Maintenance Rule by July 10,1996.
The Maintenance Rule leaves open the possibility for different expectations concerning
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what is required for full compliance. Industry expectations and NRC guidance is still g
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evolving. We certainly expect that specific program elements which we have implemented may be enhanced. However, I hope we were able to demonstrate that 130002 P. O. Box 128 San Clemente. CA 92674-0128 Fax 14 3b81490 DO o 61 G
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l Mr. S. J. Collins January 8,1997 j
i Edison has implemented the Maintenance Rule in accordance with guidance published to date.
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In preparing for our Maintenance Rule implementation, Edison was fortunate that we have had in place for many years a comprehensive corrective action system, l
well-qualified system engineers, computer-based maintenance records, and computer-based tracking and trending programs. We were therefore able to achieve j
compliance with the Maintenance Rule by using our existing programs, rather than j
developing new programs. As Mr. Gwynn noted in his January 3 opening remarks, j
Edison has a good maintenance program with good system performance and reliability.
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While we look forward to improving our program as the industry /NRC experience j
evolves, we believe it is factually correct that goals, where required, were in place on j
July 10,1996. In accordance with the Rule and NUMARC/NEl Guideline 93-01, we l
expect that in most situations, goals required by (a)(1) can be set at the system level i
and will be identical to the performance criteria in both value and unit. During our j
meeting, we learned that the expectation of your staff is that goals should generally be j
something different than the values used for performance criteria. We believe it i
appropriate to continue the dialog on this point at a later date.
During our discussions, we discovered that a misunderstanding occurred when it was j
erroneously assumed that our subsequent administrative documentation efforts, which j
we labeled " Maintenance Rule Evaluations (MREs)", constituted the establishment of
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our goals. As detailed in Enclosure 2, in 1995 Edison revised our State of the System j
Report. Copies of selected State of the System Reports were provided to the i
inspectors during their on-site inspection, and to you at our January 3 meeting. As we 4
l discussed, the MREs were separate and distin, t from the State of the System Reports, and were not required for Edison to comply with the July 10,1996 Maintenance Rule j
implementation date.
In the meeting, we explained how our Expert Panel treated smoke dampers as components of the Control Room Emergency HVAC System, establishing performance criteria at the system level. These dampers were erroneously included with risk significant equipment and when discovered, the Expert Panel then reclassified them correctly as non-risk significant. We described how we then applied plant level performance criteria to the smoke dampers. We agree that use of plant level criteria for these dampers was not sufficient to ensure the function of the dampers will be maintained. We will develop specific performance criteria, and will
Mr. S. J. Collins January 8,1997 i
be prepared to discuss the matter during the Maintenance Rule baseline inspection scheduled for later this year.
Finally, our meeting enabled us to re-emphasize that Edison has used Probabilistic Risk Assessment (PRA) in almost all phases of the development of performance criteria for availability and reliability. The San Onofre Safety Monitor, a real-time safety assessment monitor, provides us with continuing PRA insights. The availability portion of the performance criteria were checked using PRA approaches and found to be satisfactory. The reliability portion of the performance criteria was developed based on actual plant performance as monitored by the safety monitor. I hope that you have been reassured that our Maintenance Rule implementation fully benefited from PRA insights, as required by 10 CFR 50.65(a)(2).
If there is any additional information you require, please call me.
Sincerely,
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Enclosures:
cc:
Document Control Desk L. J. Callan, Regional Administrator, NRC Region IV T. P. Gwynn, Director, Division of Reactor Safety, NRC Region IV S. C. Black, Chief, Division of Reactor Controls and Human Performance, NRR M. B. Fields, NRC Project Manager, NRR J. A. Sloan, NRC Senior Resident inspector, San Onofre Units 2 and 3 Nuclear Energy Institute l
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ENCLOSURE 1 SYSTEMS, STRUCTURES, AND COMPONENTS MEETING THE NUMARC/NEl 93-01 GUIDANCE ON JULY 10,1996
===1.
Background===
NUMARC/NEl 93-01 guidance for dispositioning SSC's from (a)(1) to (a)(2) is found in section 9.4.3. That section is repeated below:
"A goal may be determined to have been met, and monitoring of SSC performance against specific goals may be discontinued if any of the following criteria are satisfied:
- Performance is acceptable for three surveillance periods where the surveillance periodicity is equal to or less than a six month interval;
"- Performance is acceptable for two successive surveillances where the surveillance periodicity is greater than six months but no greater than two fuel cycles; or
" An approved and documented technical assessment assures the cause is known and corrected and thus monitoring against goals is unnecessary.
a "If any of these conditions are met, the SSC may be returned to the provisions of
- (a)(2)."
The provisions of section 9.4.3 were incorporated into Edison's procedures and represent the minimum conditions needed to consider returning a SSC to the provisions of (a)(2). However, since management's objective is to continue to maintain a SSC in (a)(1) until it achieves the goal of meeting the performance criteria, a system will not generally be returned to (a)(2) until many more surveillances have occurred than would be the case under 93-01.
For example, a functional failure of the SSC Auxiliary Feedwater Train S occurred in August 1993 and a repetitive failure occurred two months later in October 1993. Under Edison's approach to goal setting, the goal would not have been satisfied until 36 months following the repetitive functional failure. Whereas using the NEl criteria, the Auxiliary Feedwater Train S would have met its goal following the January 1994 surveillance and could have been removed from (a)(1).
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SSCs which would not have been disoositioned to (a)(2) usina NEl auldance on June 30.1996 i
At the end of the last quarter (June 30,1996) preceding the July 10,1996, 2
implementation date for the Maintenance Rule, all but three (3) SSCs could have been retumed to (a)(2).
The exceptions were:
Unit 3 Main Steam Safety Valves e
e Unit 2 Excore Channel D l
e Unit 3 Excore Channel A Ill.
SSCs enterina fa)(1) with the end of second auarter assessment June 30.19.91 At the end of the last quarter (June 30,1996) preceding the July 10,1996 implementation date for the Maintenance Rule, two (2) SSCs were identified as exceeding their performance criteria during the second quarter of 1996, which would place them into (a)(1) in the third quarter of 1996. Because the implementation date for the Maintenance Rule was July 10,1996, insufficient time was available to disposition these two SSCs. During NRC Maintenance Rule baseline inspections at other sites, Edison believes licensees have been allowed 30 to 60 days assess the SSCs from the end of the calendar quarter.
The two systems are as follows:
Fire Water Pump G-11S e
This pump fell below its availability performance criteria in June 1996. An Action Request (AR) was issued July 24,1996, identifying that the SSC was being placed in (a)(1).
Unit 2 Core Protection Calculator Channel A This channel entered (a)(1) as a result of a failure which occurred in April 1996, causing it to exceed its performance criteria of 5 functional failures over 36 months. It also failed to meet its availability criteria during the second quarter of 1996 due to out of service time for diagnostic testing in April 1996.
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Summarv - Establishina Goals in Accordance With 10CFR50.65(a)(1)
The basis of the State of the System Report containing Maintenance Rule performance criteria and goals were prepared for the three SSCs, discussed in Section ll above, by July 10,1996. The State of the System Report cover sheets, for the second quarter 1996, are provided in Enclosure 3.
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ENCLOSURE 2 RESPONSE TO NRC DISCUSSIONS 1.
Edison Goal Settina in Accordance with 10 CFR 50.85(aWin At the January 3,1997 meeting, the NRC proposed in part:
"10 CFR 50.65(a)(1) states, in part, that '[e]ach holder of an operating license...
shall monitor the performance or condition of structures, systems, or components, against licensee-established goals... [and that] goals shall be established commensurate with safety...' Paragraph (c) states that '[t]he requirements of this section shall be implemented by each licensee no later than July 10,1996.'
" Procedure SO123-XVI-5.3.6, ' Goal Setting for the Maintenance Rule,' Revision 0, Temporary Change Notice 0-1, Section 6.1, states, in part, that the establishing of goals shall be 'strongly considered' after exceeding performance criteria of repetitive failures.
" Procedure SO123-XIV-5.3.6, Section 6.4.3, states, in part, that goals will be monitored over such time as required to minimize the effects of random failures.
" Contrary to the above, as of July 10,1996, the licensee failed to have goals and monitoring requirements established and documented for the following 13 risk-significant structures, systems, or components which did not meet the licensee established performance criteria:
Unit 2 Auxiliary Feedwater System, Train S; e
Site Diesel-Driven Fire Water Pump; o
Site Electric-Driven Fire Water Pump; e
Control Room Smoke Exhaust System; e
Units 2 and 3 Main Steam Safety / Relief Valves; e
Unit 2 Core Protection Calculator, Control Element Assembly Calculator, e
Channel A; Unit 2 Core Protection Calculator, Channel D-e Unit 2 Excore Nuclear Instrumentation Log Power, Channel D; Unit 3 Excore Nuclear Instrumentation, Channel A; e
Unit 3 Containment Purge Isolation System Radiation Monitor, Channel B; e
Unit 3 Fuel Handling System Radiation Monitor, Channels A and B; and, e
Common Control Room isolation System Radiation Monitor, Channel B."
e At the January 3,1997 meeting, Edison stated that goals for (a)(1) systems had been established in compliance with 10 CFR 50.65(a)(1). These goals were developed and documented, as discussed below, in the State of the System Reports.
, The State of the System Reports were originally developed to provide the Nuclear Organization with a clear understanding of major plant systems. In mid-1995, the report was revised into a two page tabular format tilat identifies, grades, and trends both system level and precursor level performance parameters. These changes were made in anticipation of the coming Maintenance Rule focus on availability and reliability. System level parameters primarily reflect the actual measurement of system (or train) availability or reliability. Precursor parameters monitor system, train, or component performance parameters for declining trends which could result in a reduction in system availability or reliability. Action plans for performance improvement are required for those parameters which have unacceptable performance.
Each system is assigned an overall grade, developed based on objective measures of system performance as well as the subjective assessment of the system engineer.
Overall system grades of A through D were assigned beginning the fourth quarter of 1995. Grades of A or B were assigned to performance above the Maintenance Rule performance criteria. A grade of C or D indicated performance falling at or below the performance criteria and corrective action is required. In addition to the grades, the system engineer also denotes the trend in performance. For a negative trend on any individual parameter, an action plan is documented in the report.
In 1996, as the performance criteria and goals of the Maintenance Rule were set by the Expert Panel, they were incorporated into the State of the System Reports' bases. The goals continued to be for all systems to achieve a grade of either A or B. Should performance fall to grades of C or D, the goal was to re-achieve B or better.
II.
Control Room Smoke Damners At the January 3,1997 meeting, the NRC proposed in part:
l "10 CFR 50.65(a)(2) states, in part, that monitoring under (a)(1) is not required where it has been demonstrated that the perfonnance or condition of a structure, j
system, or component is being effectively controlled through the performance of appropriate preventive maintenance such that the structure, system, or component remains capable of performing its intended function. Paragraph (c) states that '[t]he requirements of this section shall be implemented by each licensee no later than July 10,1996.'
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" Procedure SO123-XIV-5.3, ' Maintenance Rule Program implementation,'
L Revision 0, Temporary Change Notice 0-3, Section 6.3.3, states, in part, that for non-risk significant structures, systems, or components, the plant level performance criteria will be unplanned automatic reactor scrams, unplanned capability loss factor, unplanned safety system actuation, unplanned shutdown safety functional events, abnormal radiological releases, and core damage frequency.
" Contrary to the above, since September 20,1996, the licensee failed to have adequate monitoring of the performance of the Common Control Room Complex Smoke Exhaust System in that there were no performance criteria; against which the performance would be evaluated, to demonstrate that its performance was effectively controlled through appropriate preventive maintenance."
At the January 3,1997 meeting, we explained how our Expert Panel treated the smoke dampers as components of the Control Room Emergency HVAC System, establishing performance criteria at the system level. These dampers were erroneously included with risk significant equipment and when discovered, the Expert Panel then reclassified them correctly as non-risk significant. We described how we then applied plant level performance criteria to the smoke dampers. We agree that use of plant level criteria for these dampers is not sufficient to ensure that the function of the smoke dampers will be maintained. Edison will develop specific criteria for the smoke dampers. However, Edison has already revised the Preventative Maintenance program for the smoke dampers.
Edison agreed to reexamine our use of plant-level performance criteria (i.e., unplanned automatic reactor scrams, unplanned capability loss factor, unplanned safety system actuation, unplanned shutdown safety functional events, abnormal radiological releases, and core damage frequency). This review will confirm that non-risk significant functions provided by SSC's within the maintenance rule scope are monitored by appropriate plant level or specific performance criteria. Edison will be prepared to discuss the smoke damper criteria, and the results of our re-examination of the use of plant-level performance criteria, during the Maintenance Rule baseline inspection scheduled for July 1997.
Ill.
Use of Risk Sipnificance in Setting Performance Criteria JPRA_1 At the January 3,1997 meeting, the NRC proposed in part:
"10 CFR 50.65(a)(1) states, in part, that '[e]ach holder of an operating license...
shall monitor the performance or condition of structures, systems, or components, against licensee-established goals... [and that] goals shall be established commensurate with safety...'
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"10 CFR 50.65(a)(2) states, in part, that '[m]onitoring under (a)(1) is not required where it.has been demonstrated that the performance or condition of a structure, i
system, or component is being effectively controlled through the performance of i
appropriate preventive maintenance such that the structure, system, or
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component remains capable of performing its intended function.' Paragraph (c) states that '[t]he requirements of this section shall be implemented by each j
j licensee no later than July 10,1996.'
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" Contrary to 10 CFR 50.65(a)(2), as of October 25,1996, the licensee had not demonstrated that the performance criteria used for reliability was commen-surate with safety, in that, the selected performance criteria of functional failures
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(or repetitive functional failures) within a monitoring period was used for risk-i significant structures, systems, and components within the scope of 10 CFR 50.65, regardless of their safety significance."
At the January 3,1997 meeting, Edison discussed how the performance criteria were developed based upon PRA insights and the experience gained from use of the San Onofre Safety Monitor (a PRA tool). For each of the Edison availability performance criteria, the plant specific PRA was used to verify these values would not lead to a l
significant increase in core damage frequency. All proposed values were confirmed, j-supporting the Expert Panel's initial determination that overall maintenance performance was within the plant's risk assessment.
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For the Reliability Performance Criteria, the Expert Panel considered the actual historical functional failure data for each Risk Significant System for several years.
Since the historical core damage frequency was acceptable, the Expert Panel concluded historical failure rates were acceptable. The allowable Functional Failures 1
were set consistent with this historical data. Hence, our Reliability Performance Criteria considered Risk Significance.
Edison notes that on November 6,1996, an EPRI Technical Bulletin was issued to provide Industry with additional guidance. The EPRI guidance was developed in l
response to Mr. F. Maraglia's October 22,1996, letter. Edison agrees to implement the EPRI guidance and will be prepared to discuss the matter during the Maintenance Rule inspection scheduled for July 1997.
2 ENCLOSURE 3 SONGS STATE OF THE SYSTEM REPORTS 1
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1 Page 1 - Unit 3 Main Steam Safety Valves l
Page 2 - Unit 2 Excore Channel D & Unit 3 Excore Channel A f
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SONGS STATE OF TIIE SYSTEM REPORT MS SYSTEM 2ND QUARTER 1996 Main Steam System, MFIV's, MFB V's and SBCS UNIT 2 TJNIT 3
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TREND NO CHANGE TRENo NO CHANGE A
O A lA.)a l
GRADE t
LAST4 PERIODS.-
GR.@E m
LAST4 PERIOD 1
SYSTEM LEVEL (Consider Sy*m AnudWty/ReumWUty type parameters crede of C or D or Neg l PARAMETER [,
MT 21,
_. M T 3 J_.
- .dCO51$1hNhE M,,,j?
cnAne ' TacNo cRAnexTazNo Mtee Rule Functional Failun:s - ADVs A
A
=
=
l Mtce Rule Functional Failures -MSIVs A
A
=
=
1, Mtee Rule Functional Failures -MSSVs A
C AR mm160: SE SAP #1 ON 2 MSSVs.
=
=
MSSVReliability A
A
=
=
Load Reduction A
A
=
=
SBCS Reliability A
A
=
=
l YSTEM PRECURSOR LEVEL (condder Programmatic Parameters and Precursor Parameters to Syseem Level Performaace. Credes of C or D or Negadvs tnad require comm y.;. y
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3.,
g.MT 2 *- T UNIT 3/ ~
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~ 19! EjPARAMETER ' 4;.Q ggg7,fg ggg ggg gg gCgfMENTSR fgdf*yg!"g MSIV,MFIV, and MFBVperformance B
A
+
U3 HAIMl EANNG OWSOEWE BAND DUETO
=
OAGE CAlmRA"ITON PROBLEMS. ACWAL OKAY.
MSSVquarterly stacktempemtures A
A
=
1
=
Percent of tmps OOS orfailed A
A
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=
=
Qtriy IST Valve Perfmc (ADV/MSIV bypass)
A A
=
=
SBCS Performance A
A
=
SEE SAP #2.
=
OpenEngineering Actions 17 g
INSIGNEICANT CHANGE,SEE SAP #3.
Open Corr:ctive Maintenarce Orders 116
+
86
+
Overdue / Late PMs 0
0
=
=
OpenTemp ModsAVork Amunds 0
1 N2 EGULATOR ON SKID FAILED,SEE SAP #5.
=
Leab 17
+
10 UnNcREASED NOTSIGNECANTCHANGE FROM LAST OU A RTE R. SEE S AP 84.
Housekeeping / Material Condition B
B
=
=
PREPARED BY DATE 07/29/96 COG ENGINEER JUANARMAS REVIEW AND APPROVAL DATE 07/30/96 SUPERVISOR HIRSCH, JOHN m
S' ONGS STATE OF THE SYSTEM REPORT EXCR SYSTEM 2ND QUARTER 1996 NuclearInstrumentation System UNLT 2
- UNIT 3
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Tatun NO CHANGE ratuo DECLINING ~
Q Di
- CU.ued
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y LAST4 PERIODS LAST4 PERIODS SYSTEM LEVEL (canader system Av.u.buity/neu.nalty type p.rameters cc de orcor n erN
- i PARAMt.12.R 1; isUNIT L,.. gyW3.fg fj%,
qfgbTSYi CRADE. TREND CRADELTREND
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Ch el A Availdility A
+
D 8^' "**' l ' '- ***
- 8 ^^ ' 33 7 Chw+1B Availdility A
+
A
+
Clanrel C Availdility A
4-A
+
Chs+1D Availdility D
A
+
SAP hem 1.
od Sa6s AR960601333 Mtee Rule FmionalFailums -Channel A B
A
=
=
Mtee Rule Functional Failures -ch,nrel B A
A
=
=
Mtee Rule Funedonal Failmes -Chnnnel c A
A
=
=
Mtee Rule Functional Failures.ch,nnel D D
A 8"2= 1 *
- 2 8a *a" coal see m
=
=
s Safety ek'nnel Relisility C
C SAP n-1,Ia 3. k con oog seeg a Startup & Wide Range Chnnnr1 Relisility A
A
=
8^P 8*= 4
=
YSTEM PRECURSOR LEVEL (tfengder Programmade Parameters and PrecursorPerameters to System Level Performance. Credes of C or D orNegadve
$._...) hj &,, _g,y;g ? ~ $ JUNIT2%l %QUNTY3L, %' W
/%
- ^y Q - Q f %iW
- ;D yd m -
_ m we -
Y cRADEZTREND CRADESTREND
+ - &! E c d5 Dub
~4 Spurious Actuations D
D SAP hem 3 Hardwa= Performance (Switch, Connector)
B D
saaems i
Elec. Circuit / Component Performance B
+
C 8" Rat i
OpenEngineering Actions 9
0
+
SAPh m 1a3 Open Com:ctive Maintenance Orders 15 10
+
suh-t.3,a5 Overdue / Late PMs 0
0
=
=
OpenTemp ModsAVo& Amunds 0
0
=
=
Housekeeping / Material Condition A
A
=
=
i PREPARED BY DATE 07/26/96 COG ENGINEER STEVE FOGLIO REVIEW AND APPROVAL DATE 07/26/96 SUPERVISOR BUD BOSTIAN
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