ML20046B934
| ML20046B934 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 07/30/1993 |
| From: | Mark Miller, Narbut P, Peterson S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V), Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20046B929 | List: |
| References | |
| OLA-2, NUDOCS 9308090039 | |
| Download: ML20046B934 (18) | |
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pa mn MRMEPCNrienCE W E:
July 30,1993 6
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93 J130 P / :56 UNITED STATES OF AMERICA j
NUCLEAR REGULATORY COMMISSION -
BEFORE THE ATOMIC SAFETY AND LICENSING BOARD.
In the Matter of
)
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Docket Nos.
50-275 OLA-2 PACIFIC GAS & ELECTRIC CO.
)
50-323 OLA-2
)
(l'%blo Canyon Nuclear Power Plant,
)
(Construction Period Recovery)
Units 1 & 2)
)
NRC STAFF TESTIMONY OF PAUL P. NARBUT, MARY H. MILLER AND SHERI R. PETERSON-i REGARDING CONTENTION 1: THE SURVEILLANCE AND MAINTENANCE PROGRAM AT DIABLO CANYON Ql.
State your full name and current position with the NRC.
ANSWER
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Paul P. Narbut, Regional Team Leader, Region V, Division of Reactor Safety and Projects.
I Mary H. Miller, Senior Resident Inspector (Diablo Canyon), Region V.
Sheri R. Peterson, Senior Project Manager, Office of Nuclear Reactor Regulation.
Q2.
Have you prepared a copy of your Professional Qualifications?
l ANSWER (All) A copy of our Professional Qualifications is included in Staff Exhibit 1.
9308090039 93073o
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{DR ADOCK 05000275 PDR
t Q3.
What is the purpose of your testimony?
ANSWER (All) The purpose of this testimony is to address San Luis Obispo Mothers for
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Peace's Contention I which reads as fdlows:
The San Luis Obispo Mothers for Peace contends that Pacific Gas and 1
Ele.ctric Company's proposal to extend the life of the Diablo Canyon Nucles Power Plant for more than 14 years (Unit 1) and almost 15 years (Unit 2) should be denied because PG&E lacks a suf5ciently effective and comprehensive surveillance and maintenance program.
Q4.
Please describe, in general, maintenance and surveillance programs at nuclear power plants.
ANSWER (Peterson) Maintenance is defined as the work of keeping something in suitable condition. There are basically two kinds of maintenance, preventive and corrective.
Preventive maintenance is regularly scheduled work performed on structures, systems or components that keeps failures from occurring due to predicted component degradation.
Industry-wide operating experience is often taken into account in determining what type preventive maintenance is necessary and how often it should be performed. Corrective i
maintenance is performed after a failure occurs, or a component exhibits degraded capability.
The surveillance tests are conducted to identify failures or degraded E
performance that needs to be corrected prior to a system being called upon to perform a safety function.
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Q5.
Please describe the reporting system by which the Licensee documents failures or degradation of structures, systems or components.
ANSWER (Peterson) A nonconformance report (NCR) is a mechanism for personnel to l
document certain deficiencies at Diablo Canyon, initiate corrective action and establish a completion schedule for resolution of a nonconformance. In Diablo Canyon procedure OM7.ID3, the Licensee defines nonconformance as: A quality problem that constitutes a significant condition adverse to quality. To be classified as a nonconformance, the i
i quality problem must satisfy one or more of eight criteria outlined in the procedure. The criteria include NRC violations, programmatic or implementation breakdowns, design deficiencies, defects, frequently recurring and NRC reportable events. If the problem identified is determined to be a nonconformance, the Licensee's nonconformance report l
(NCR) documents the event description, root cause determination, safety analysis, and i
action taken to correct the nonconformance and prevent recurrence.
Licensee event reports (LER) are submitted to the NRC pursuant to 10 CFR 50.73. The threshold for requiring an LER is higher than the threshold for an NCR. Typically the Licensee issues anywhere from 60 to over 100 NCR's each year compared to 20 to 30 LER's each year. While NCR's are used internally at Diablo Canyon, LER's are submitted on the Licensee's public docket and used by the NRC for i
trending purposes and identifying significant events. Both reports are a means for licensees to document self-identified problems.
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Q6.
Please describe the NRC inspection program for maintenance and
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surveillance at Diablo Canyon.
li ANSWER (Narbut) The inspection program for maintenance and surveillance at Diablo Canyon consists of several elements.
First, there are the monthly inspections performed by the residents inspectors.
Our procedures set a goal of observing tour maintenance activities per month. Our procedures require the resident inspectors to observe surveillance testing in a unit each I
month and to observe a surveillance test in detail every other month. Thus, the resident l
inspectors observe about 48 maintenance activities a year and about 18 surveillance tests.
Generally, they do more than the minimum during refueling outages.
Second, our inspection program inn.lves regional specialists performing required (core) inspections in such areas as inservice examinations (examining a portion of the important welds periodically) and inservice testing (examimng the testing as required by the American Society Mechanical Engineer (ASME) codes adopted by the NRC at 50.55a).
Also, the NRC has a van which performs independent nondestructive j
examinations, such as X-ray of welds. This van and our chief nondestructive examiner i
examined Diablo Canyon's work in 1987 and found their nondestructive examination l
s programs sound.
l Third, regional and NRC headquarters inspectors performed special inspections in specific areas of interest such as erosion / corrosion of piping, motor operated valves, procurement, environmental qualification, and the 6th diesel generator installation.
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Fourth, NRC management has periodic meetings with PG&E management. These meetings have often dealt with maintenance and surveillance issues such as a meeting
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held in July 1993 on steam generator tube inspection methods and plans.
l Finally, periodically there have been team inspections. These are multi-discipline i
teams ofinspectors looking at a specific topic in depth. There was a team inspection that l
examined maintenance at Diablo Canyon in 1988. Be last team at Diablo examined l
shutdown risk and was led by an NRC headquarters specialist. The team found PG&E's f
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activities to be sound.
i The NRC has devoted considerable resources to inspection of maintenance and l
surveillance at Diablo Canyon. The area has accounted for about 10-20% of our l
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inspection effort. The NRC has expended a total of about 4500-8500 direct inspection I
hours per year at Diablo.
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Q7.
Describe the performance of Diablo Canyon's maintenance and i
j surveillance program.
l ANSWER (Narbut, Miller) The performance of maintenance and surveillance at Diablo is i
considered to be superior and clearly supportive of safe facility operation. Their performance has been, at worst, good and has improved over the years. Gradual trends l
i over the past seven years show a reduction in the number of equipment failures, reduction j
l of safety significant problems, increased management involvement in maintenance issues, I
and more timely identification and resolution of problems. Some examples of poor i
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.. 9 performance in each of these areas continue to be identified. However, these examples j
have been of decreasing frequency and safety significance.
Q8.
Have there been problems identified with maintenance and surveillance at Diablo Canyon?
ANSWER (Narbut) Yes, there have been problems associated with Diablo Canyon mainte-t nance and surveillance; however, these problems do not show any breakdown in Diablo Canyon's surveillance and maintenance program. Problems have been identified in NRC inspection reports, licensee event reports, and management meeting reports. Improper r
maintenance of the containment fan cooler units (CFCUs) and the corrosion of the diesel fuel oil piping are two examples. NRC follow-up of these problems assessed whether the Licensee had done a thorough job of understanding the cause and breadth of the problem and whether the Licensee had taken prompt and effective corrective action.
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Q9.
Has the Licensee dealt with these problems effectively?
ANSWER (Narbut, Miller) Yes, generally the Licensee has dealt with problems in the maintenance and surveillance areas effectively. The Licensee has corrected a great majority of the problems promptly. Their corrective actions generally addressed the specific problems as well as more generic concerns, if applicable. Many of the problems noted were initially identified by PG&E through their maintenance and surveillance j
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program. The scope of corrective actions typically included changes to equipment, procedures, drawings, training, maintenance practices, or design documents. In cases where the Licensee's actions were untimely or inadequate, the NRC has issued violations.
In all cases, the NRC performs follow-up of the significant problems to ensure effective i
i corrective actions were taken. Progress continues in the maintenance and surveillance area as a result of PG&E's effectively resolving the problems noted.
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Q10. You mentioned a problem with Containment Fan Cooler Units (CFCUs) at Diablo. Would you please describe that problem.
ANSWER i
i (Narbut) There were two problems with the containment fan cooler units (CFCUs) at Diablo. The first problem, found by plant personnel, surfaced in early (February) 1992 and involved the failure of the backdraft dampers to close. The second problem was discovered in late (October) 1992 and involved cracking of the backdraft damper blades. Backdraft dampers are used to prevent reverse flow through those CFCUs not in operation.
The CFCUs are used to cool the containment atmosphere and equipment located
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in the containment building in normal operation and, in a LOCA, they serve to limit the pressure peak in containment in conjunction with the containment spray system.
In January 1992, the Licensee identified that some of the counterweights for l
4 CFCU backdraft dampers in Unit 2 had fallen off. The counterweights close the d
dampers. Later, the Licensee began a review of the installation and maintenance history 1
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of the backdraft dampers.
The subsequent NRC and Licensee conclusions were:
(1) errors had occurred during the previous refueling outage in reassembling the dampers in Unit 1, (2) post-maintenance testing instructions were not sufficient (3) reinspections done in March 1992 were done without appropriate procedures, and (4) the Licensee had not done an in-depth review a year earlier in March of 1991, when a bolt was found on adjacent deck grating and fan reverse rotation was noted. A thorough follow-up of these pre. rsors could have led to the discovery of the subsequent problems with the backdraft dampers.
The CFCUs were subsequently analyzed to have been operable during the entire period, but this was not evident at the time. In October 1992, cracking due to fatigue i
was discovered in some of the backdraft damper blades in Units 1 and 2. The blades were replaced with blades of higher strength material.
Several causes were identiGed by the NRC for why the backdraft dampers problems were not discovered until February 1992: (1) the quality organization was not sufficiently involved; (2) the maintenance organization tried to resolve problems such as reverse rotation and broken bolts without involvement of the engineering organization; and (3) there was a lack of attention to detail by maintenance personnel in performing the 1
reassembly work and communications regarding damper conditions were not effectively
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relayed to PG&E management.
The nnal resolution of the CFCU problems took several months. Subsequently, i
the Licensee put together a team to perform an integrated review of the problems. The maintenance and surveillance test procedures were improved. In addition, as a result of v
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. l the team's recommendations, the Licensee provided guidance to engineering personnel to define their responsibilities related to maintenance and component trending, added i
additional personnel to the system engineering staff, reemphasized more direct communications between those dealing with plant problems, re-evaluated inspection activities, re-emphasized the development of a questioning attitude in the review of plant j
problem reports, and required additional training in the evaluation of degraded plant equipment.
i Qll. Has there been degradation of high voltage electrical cables for safety l
related pumps at Diablo? If so, please describe this degradation.
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ANSWER (Narbut) In Licensee Event Report 93-05, PG&E reported five instances of degradation in the cable insulation for 12KV and 4KV cables that supply power to plant components. The problem is discussed in NRC Inspection Rep,rts 93-03, 93-07 and 93-17. PG&E has preliminarily concluded that all of the 12KV and possibly also the 4KV cable failures occurred due to a combination of submergence of the cables, and chemical attack accelerated by the submergence. The submergence was caused by insufficient preventive maintenance of the sump pumps which were designed to remove water from the cable conduits. The NRC inspection verified that the Licensee has repaired the inoperable pumps and initiated a preventive maintenance program for them.
t Further, all of the failed cables have been replaced.
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r 1 l PG&E is continuing work to identify the cause of the 4KV cable failure. NRC inspections concluded that the Licensee's follow-up actions in response to those equipment and cable failures have been adequate and reasonably thorough. The NRC concluded that plant safety had not been significanuy reduced by these cable failures, due to the presence i
of other, unaffected cables for redundant safety-related pumps.
Q12. Please explain the NRC findings raised in the basis of the ccatention regarding degraded diesel fuel oil piping and a failed reactor cavity level instrument.
ANSWER (Narbut) Diesel Fnel 0- Pinine Corrosion
- The diesel fuel oil piping corrosion was identified by the Licensee during cleanup of an unrelated caustic spillin the area of the underground pipe. Piping had corroded significantly to the point that the wall was thin. The Licensee's actions subsequent to the discovery of the corrosion were thorough in identifying the amount and extent of cerrosion and correcting the problem. Licensee lor term actions, which
'aded looking for similar situations in other systems, were identified, appe ed to be adequate, and will be followed up.
The NRC concerns were that the problem first surfaced in February 1990, and actions at that time were not sufficient. The problem had been identified in February of 1990 during the performance of the 10 year pressure test of the system. This test requires a visual check for leaks but not for corrosion. The Licensee actions were: 1) to i
correct the problem found and 2) to shorten the test frequency to five years. This action i
was not sufficiently comprehensive or conservative. An additional NRC concern involved
- 11 the coordination between the maintenance and operations organizations, in that the other fuel oil system had been taken out of service leaving the corroded system in service.
Only later did the Licensee determine, by analysis, that the fuel oil system had been operable despite the corrosion. In summary, the surveillance test designed to catch this scrt of problem did. However the actions in 1990 were not sufficient to correct the problem.
4 Unit 2 Reactor Cavity Sumo: Reactor cavity sump level indications are required by Technical Specifications as one of several methods of determining if there are leaks in piping in the containment. The inoperable Unit 2 reactor cavity sump level indications were discovered in November 1990 during surveillance testing. After Licensee corrective actions were completed, in October,1991, an NRC inspector identified that a channel had again failed and had been inoperable for the preceding 13 days. The NRC concern was that operators had not recognized the problem.
The problem was one where the instrument failed to a zero reading, which was the w; mal reading. Consequently, the 1
problem is hard to identify using the control roon le The failure is detectable i
when the computer Safety Parameters Display Syste.
mereen is used. The l
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i reading is shown as a flashing value in a different color on one screen, and with a i
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question mark on a different screen. The NRC concern was again operator awareness, o
not equipment aging.
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The NRC issued a violation for this failure to maintain the equipment in an operable condition. The Licensee's subsequent corrective actions appropriately addressed each of the concerns associated with the level indication, as well as generic actions to i
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ensure that instruments like the sump level indications are properly maintained and monitored. This item has been closed.
Q13. How do these NRC findings reflect on PG&E's performance in maintenance and surveillance?
ANSWER (Narbut, Peterson) The diesel fuel oil corrosion issue is something the maintenance and surveillance program is designed to catch. The program did catch the problem, but i
did not fully resolve it in this case, due to insufficient action when the problem first surfaced.
The reactor cavity sump level indication issues reflected a weakness in the performance of a surveillance test. It is clear from other NRC inspection activities that the operator knowledge concerns found with the level indication surveillance are not widespread.
In summary, these were negative examples of PG&E performance in surveillance, but these examples did not reflect the overall performance in the maintenance and surveillance area.
Q14. Does the timeliness of corrective action represent a pervasive problem at Diablo with regard to maintenance and surveillance?
ANSWER (Narbut, Miller) Timeliness of corrective action has been a management issue with i
Diablo in past years. It does not currently represent a widespread problem at Diablo i
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t Canyon. Typically, timeliness problems have occurred in two areas: correction of equipment failures and timeliness of engineering support.
Equipment: In the vast majority of cases in which a problem has been identified concerning equipment, by either the NRC or the Licensee's staff, the Licensee has l
promptly started corrective actions. The time for the Licensee to fix equipment problems j
has been appropriate to the safety significance. The Licensee has typically returned equipment to service well before expiration of the time allowed by the Technical Specification, and has had excellent performance and management involvement in maximizing equipment availability.
Exceptions were the Containment Fan Cooler Units (CFCUs), discussed earlier, l
i and the main feed pump speed controller problems in early 1992. Although the speed l
l controllers are not safety-related, the NRC emphasized that more timely management and j
i design engineering involvement in precursor problems could have avoided a plant trip.
j Engineering: Engineering problems may affect maintenance and surveillance j
i activities. The Licensee has demonstrated good, rather than outstanding timehness m l
I these areas.
However, a lack of timeliness of engineering activities in support of i
maintenance and surveillance activities has not been a persistent problem.
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Overall, the maintenance staff has continued to improve their response to problems j
i by identifying, analyzing and correcting maintenance and surveillance problems promptly.
Examples of this improvement were the identification and correction of an incorrect RCS leakage surveillance; prompt, in-depth evaluation and compensatory action for AFW I
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pump steam admission valve problems; and improvement of the clarity of some instrumentation and control surveillances.
t Q15. Would untimeliness of corrective action have a significant effect on aging?
ANSWER (Narbut; 'Jntimeliness could have an effect on the plant, if aging problems were not thoroughly assessed and dealt with. Many facets of plant aging are well understood and are dealt with routinely, through maintenance activities such as preventive I
maintenance. For instance, many rubber and polymer products have a definite life span L
and must be replaced periodically. Other problems such as erosion-corrosion of piping t
were a surprise to the industry and were eventually understood and dealt with effectively.
Diablo Canyon has been effective in dealing with emerging new aging issues. An example is the fact that Diablo basically alerted the industry to the issue of counterfeit l
replacement parts. The high voltage cable degradation is an ongoing issue which will l
need to be resolved but which seems to be getting the proper amount of Licensee attention.
j Q16. Would these problems be age limiting to the plant?
ANSWER (Narbut) In general the answer is no. But clearly, some problems, if undetected, would have had a deleterious effect on plant operation. As discussed with the examples l
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of aging issues in Question 12, like erosion-corrosion, PG&E generally does a good job in dealing with emerging aging issues.
Q17. Why do NRC inspection reports seem to address problems at Diablo rather than strengths, if Diablo is perceived to be a good performer?
I ANSWER l
(Narbut) For the cases where the NRC observes strengths or finds no problems, inspection reports usually contain very little discussion of these positive areas. On the other hand, discussions of problem areas are generally thorough and in depth. This is consistent with the NRC focus on improving safety. NRC inspections and inspection reports focus on identifying problems and assessing the effectiveness oflicensee actions.
This usually results in a report with a negative tone.
Q18. Does this complete your testimony with regard to the surveillance and maintenance program at Diablo Canyon?
ANSWER (All) Yes.
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t PROFESSIONAL QUALIFICATIONS PAUL P. NARBUT ORGANIZATION:
Nuclear Regulatory Commission Region V Division of Reactor Safety and Projects TITLE:
Regional Team Leader EDUCATION:
B.S. Nuclear Engineering State University of New York, Maritime College l
Graduate work in "uclear Engineering Oak Ridge School of Reactor Technology EXPERIENCE:
1991 - Present Nuclear Regulatory Commission, Region V.
Regional team leader.
Led team inspections at Region V sites in accordance with NRC inspection procedures.
Additionally, conceived, developed and performed the inspection procedure for the examination of reactor plant testing. Also, was designated as the Region V representative to the NRC's. revised maintenance rule working group. Subsequently, participated in the development of the new inspection procedures for maintenance inspection and the public workshop for the revised procedures.
In addition, served on the NRC's l
working group to revamp inspector training, and taught a portion of the initial presentation of the revised course.
l 1986 - 1991 Nuclear Regulatory Commission, Region V.
Senior Resident Inspector at Diablo Canyon.
Inspected and supervised the inspection of two resident inspectors at Diablo Canyon. Managed and coordinated the inspections of regional and NRC headquarters personnel. Developed and presented NRC management positions on Diablo Canyon's performance for management meetings. Was selected by the NRC, as an exemplary inspector, to represent the United l
States in a safety exchange program with the (then)
U.S.S.R. following the Chernobyl accident.
1984 - 1986 Nuclear Regulatory Commission, Region V.
Operations Inspector.
Formally qualified as an operations inspector by the NRC training program.
Performed operations inspections at Region V sites.
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1978 - 1984 Nuclear f.egulatory Commission, Region V.
Construction Inspector. Formally qualified as a c0nstruction inspector by the NRC training program.
Performed construction inspections at Region V sites.
Areas of expertise included welding, piping, structural steel, concrete, and non-destructive examination.
1972 - 1978 Department of the Navy, Mare Island Naval Shipyard.
Served as an engineer and office and field supervisor in the refueling, overhaul, and modification of operating nuclear submarines. The disciplines included piping, mechanical, testing and refueling.
Developed a training and qualification program for craftsman for high radiological exposure jobs. Was certified and served as a Chief Test Engineer and a Chief Refueling Engineer.
1967 - 1972 Department of the Navy, Mare Island Naval Shipyard.
Served as an engineer in the construction of nuclear submarines. Disciplines included piping, mechanical, structural, and radiation shielding.
Resolved specification and installation problems.
1963 - 1967 Atomic Energy Commission, Space Nuclear Propulsion Office, Served as the assistant reactor physicist and radiation shielding analyst for the nuclear rocket program.
Performed technical contract administration for the reactor and space vehicle contracts. Also performed independent shielding and reactor core design.
LICENSE:
Third Assistant Engineer, Steam and Motor Vessels, any Horsepower AWARDS:
Received many awards from the Navy and the NRC for outstanding performance and important inspection findings.
PROFESSIONAL QUALIFICATIONS MARY H. MILLER ORGANIZATION:
Nuclear Regulatory Commission Region V Division of Reactor Safety and Projects TITLE:
Senior Resident Inspector, Diablo Canyon EDUCATION:
B.S.
Chemical Engineering Rice University, Houston, Texas Graduate work in Nuclear Engineering Naval Reactors Design School Bettis Atomic Power Laboratory EXPERIENCE:
1993 - Present Nuclear Regulatory Commission, Region V.
Senior Resident Inspector at Diablo Canyon.
Inspected and supervised the inspection of two resident inspectors at Diablo Canyon. Managed and coordinated the inspections of regional and NRC headquarters personnel.
Developed and presented NRC management positions on Diablo Canyon's performance for management meetings.
1991 - 1992 Nuclear Regulatory Commission, Region V.
Resident Inspector at Diablo Canyon Performed inspections of reactor operations at Diablo Canyon. Acted as Senior Resident Inspector in the absence i
of the Senior.
Participated in the Diagnostic Evaluation Team inspection of the Fitzpatrick Nuclear Power Plant, and performed reactor start-up operations inspections of the Trojan Nuclear Power Plant.
i 1989 - 1991 Nuclear Regulatory Commission, Region V.
Engineering Inspector at all Region V plants. Formally qualified as a reactor inspector by the NRC training program. Performed individual inspections at all Region V sites and participated in team inspections in areas of electrical distribution, fire protection, maintenance, design changes, and other areas of reactor plant operations.
Led the Appendix R team inspection at the Trojan Nuclear Power Plant. Planned and coordinated several other group and team inspections.
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