ML20046B940
| ML20046B940 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 07/30/1993 |
| From: | Madden P, Mark Miller NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V), Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20046B929 | List: |
| References | |
| OLA-2, NUDOCS 9308090046 | |
| Download: ML20046B940 (13) | |
Text
TsEL/,TED C0ili!ESPONDENCE
- ' JulyQ0,1993 s
n:- c UNITED STATES OF AMERICA 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.
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50-323 OLA-2
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(Diablo Canyon Nuclear Power Plant,
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(Construcion Period Recovery)
Units 1 & 2)
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NRC STAFF TESTIMONY OF PATRICK M. MADDEN AND MARY H. MILLER CONCERNING CONTENTION 5:
THERMO-LAG AND FIRE WATCHES AT DIABLO CANYON Ql.
State your full name and current position with the NRC.
ANSWER l
I Patrick M. Madden, Senior Fire Protection Engineer, Office of Nuclear Reactor l
Regulation.
Mary H. Miller, Senior Resident Inspector (Diablo Canyon), Region V.
Q2.
Have you prepared a copy of your Professional Qualifications?
ANSWER (All) A copy of our Professional Qualifications is included in Staff Exhibit 1.
9308090046 930730 PDR ADOCK 05000275 C
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Q3.
What is the purpose of your testimony?
ANSWER 7
(Madden) The purpose of this testimony is to address the adequacy of PG&E's adherence to interim fire-protection measures to compensate for Thermo-Lag fire protection features declared inoperable at Diablo Canyon, pending resolution of the generic Thermo-Lag issue by the NRC Staff.
Q4 Is there a problem with Thermo-Lag at Diablo Canyon?.
ANSWER (Madden) Thermo-Lag fire barrier problems are considered to be generic to the industry. These problems, in brief, are: that certain Thermo-Lag fire barriers may not provide the level of fire resistance required to satisfy the NRC fire protection requirements; that Thermo-Lag may burn more readily when exposed to fire than original!y believed by the NRC and licensees; and that the ampacity derating factors used by licensees to derate their power cables may not be great enough to actually account for the insulating effects of the Thermo-Lag material. The majority of plants use Thermo-Lag to satisfy NRC fire protection requirements.
The amount of Thermo-Lag installed at Diablo Canyon to satisfy these l
requirements is considered moderate.' The Licensee has replaced all Thermo-lag in the
' Moderate is defined as a plant which has installed between 100 and 1000 square feet or between 100 and 1000 linear feet of fire barrier material.
Unit 2 containment and plans to replace all Thermo-lag installed in the Unit 1 containment during the next refueling outage scheduled for February 1994.
Q5.
Does the Staff consider on a generic basis that interim compensatory measures can provide the protection required by the NRC fire protection program pending resolution of the Thermo-Lag issue? Please explain.
ANSWTR (Madden) Yes. Nuclear power plant fire protection programs are based on defense in depth. This defense-in-depth approach is based on the following three principles (1) preventing fires from occurring, (2) for those fires that may occur despite the effectiveness of the fire prevention program, fires must be detected and suppressed quickly, and (3) despite the effectiveness of the fire fighting activities, physical separation is required to be provided for safe shutdown functions, assuring the ability to achieve and maintain safe shutdown conditions.
The objective of this defense-in-depth approach is to create a balance between these three principles. Therefore, when a weakness in the fire protection program occurs that affects one of these principles, this weakness can be compensated for by strengthening fire protection activities covered by one or both of the other principles.
For example, if redundant safe shutdown trains are located in a given plant area, the defense in depth would assure plant safe shutdown capability by protecting one train with a one hour fire barrier. In addition to the fire barrier, this plant area would be provided with area-wide smoke detectors and an automatic water fire sprinkler suppression system. Under this condition, ifit were determined that the fire barrier was
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degraded, the licensee would be required, by either plant technical specifications or license condition, to impose a compensatory measure which would strengthen the defense in depth. In this case the early warmng fire detection and the automatic fire suppression systems are operable and capable of detecting and controlling a fire quickly, even though the fire barrier is degraded.
In order to provide reasonable assurance that fire hazards in the area of the degraded fire barrier are minimized, licensees use roving fire watch patrols. This concept of allowing alternative actions to compensate for an inoperable condition or component is used in various programs associated with the operation of nuclear power plants and has always been an integral part of NRC regulatory requirements.
The NRC has evaluated the use of fire watches to compensate for any degradation in the effectiveness of required fire barriers, and has concluded that fire watches continue I
to assure adequate protection of the public health and safety. In addition to the defense-in-depth approach, the NRC resident inspectors tour accessible areas of the plant each week to observe, among other things, fire hazards and fire fighting equipment to verify operational safety.
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Q6.
Please describe the use of fire watches as a compensatory measure.
ANSWTR (Madden)
Fire watches are personnel trained and dedicated by licensees to inspect for the control of ignition sources and combustible material, to look for conditions that may indicate an incipient fire, provide prompt notifications of fire hazards and fires, i
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5 that may indicate an incipient fire, provide prompt notifications of fire hazards and fires, and, if within skills of their piant specific training, take actions to begin incipient fire suppression activities.
There are two types of fire watches. The first type is the roving fire watch. This fire watch patrols the area of the inoperable fire protection feature (e.g., fire barrier, fire door) on an hourly basis. During this patrol the fire watch is enhancing plant fire prevention by looking for and identifying fire hazards in the area of the inoperable fire protection feature. The second type of fire watch is a continuous fire watch.
A continuous fire watch is posted in the area of the impairmeint at all times. The purpose of this fire we.:h is to enhance fire prevention and the ability to detect a fire in this area if one were to occur. A continuous fire watch is generally used to compensate for the fire protection features in plant areas where either automatic fire detection capability is inoperable or is not provided.
Q7.
Have instances of missed fire watches and disabled fire barriers at Diablo Canyon been identified by the Licensee or the Staff? Please explain.
ANSWER 1
(Miller) Yes. There have been nine identified instances of missed fire watches and disabled fire barriers at Diablo Canyon since the beginning of 1990. Their description follows:
(1)
LER 1-90-18 described an incorrectly assembled closing trip mechanism
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i discovered on December 21, 1990, on a ventilation fire damper in the
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cable spreading room. The incorrect assembly was discovered during the periodic surveillance test of the fire damper. So, in a sense, the test did its job in identifying a problem. The misassembly resulted in the inability of a fire damper to close as designed upon carbon dioxide system actuation. Its ability to close as designed in the event of a fire was not affected (due to the thermal actuation of its fusible link).
The inability of the fire damper to close on carbon dioxide system actuation caused the carbon dioxide system in the cable spreading room to be considered inoperable, in that the necessary concentration of carbon dioxide could not be assured. This condition existed for about a year.
However, hourly fire watches covered the area during the period and, as previously stated, the damper would have functioned in the event of a fire.
Additionally, fire detection equipment in the area would have alerted operators on the floor above promptly and local fire suppression equipment could have been utilized.
(2)
LER 1-91-15 described a failure to perform a roving hourly fire watch on September 17,1991,in some of the safety related equipment rooms. The person conducting the fire watch was delayed leaving the radiologically controlled area, and was not able to contact his supervisor in time to prevent violation of the Technical Specification requirement.
For corrective actions, an incident summary was prepared and reviewed with fire watch personnel, and included in fire watch training.
Written instructions have been provided to personnel for actions to take if delays occur on rounds.
(3)
LER 1-91-20, dated March 31,1992, described a damaged ceiling tile in the solid state protection system room which caused the Halon fire suppression system to be declared inoperable. The system was called inoperable because, if actuated, a sufficient concentration of Halon in the room couldn't be guaranteed. The situation existed for 13 days. However, the room fire detection equipment was operable and other manual fire suppression equipment was available. Also, the adjacent space, the control i
room, was continuously manned.
(4)
LER 1-92-07 described a situation where, on June 20,1992, the hourly fire watch for an area in the turbine building was purposely suspended because of a noxious chemical spill in the area.
Fire watches were suspended for about eight hours while the noxious fumes were cleared.
However, firefighters and security personnel were available and in the immediate area throughout the eight hour period.
(5)
LER 1-92-14 described three situations, on September 3,4 and 15,1992, when a continuous fire watch was not in place while smoke detectors were inoperable and fire banier impairments existed in the detection zone. The root cause for the three events was personnel error. The immediate corrective actions for the three separate events were to establish a i
i continuous fire watch, repair the faulty smoke detector and reset the alarm
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1 i j system. The corrective actions to prevent recurrence included revision of 1
l applicable procedures to: (1) more accurately reflect the status of field construction activities that impact fire barriers; (2) clarify the effect of alarming detectors; and (3) clarify the impact that an inoperable fire detector has on compensatory measures for fire barrier impairments.
(6)
LER l-92-28 described two fire detection computer failures: one on October 1,1992, and one on November 26,1992. The computer failures should have annunciated in the control room, but did not. This failure to annunciate was caused by a software error. The action statement, to establish fire watches, was exceeded for twenty-nine (29) minutes in one case and about fifteen (15) hours in the other. The missed compensatory action for the second instance was the establishment of a continuous fire watch in the control room, which is a continuously manned space. The Licensee's actions were satisfactory and aimed at resolving the software deficiency and improving software quality assurance.
(7)
LER 2-92-01 described six instances of inadequate circuit separation in both units. The deficiencies were identified on February 14,1992, by the Licensee as a result of a comprehensive study of fire protection safe shutdown cable separation issues. The configurations were installed during plant construction but came under review in 1991. The study found i
several problems in cenain installations. For instance, the diesel generator field circuit cables were separated by less than 10 feet in one unit. This
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. i failure to provide 10 feet of separation would require one of the cables to be protected by a fire barrier. The Licensee found neither cable had a fire barrier.
Another example involveJ the emergency diesel generator stop switch enclosures. The stop switches were enclosed in a fire barrier made cf Thermo-Lag. However, the installation was not in accordance with vendor requirements. The enclosures have since been replaced with Pyrocrete enclosures.
Licensee compensatory actions and corrective actions appeared appropriate.
(8)
LER 2-92-06 described two instances, one on October 30,1992, and one on November 14,1992, in which operators did not recognize that required compensatory fire watches had not been established. The operators had apparently grown accustomed to spurious alarms from certain fire detectors.
In the two cases reported, the operators had assumed compensatory measures had been taken because there had been four previous instances of spurious alarms which had initiated compensatory measures. The action statement was exceeded for thirty-one (31) minutes in one instance, and about thirty-seven (37) hours in the other. In the second instance, although a continuous fire watch was not initiated as required, an hourly roving watch was in effect in the area.
(9)
LER l-92-08 described the failure to establish a continuous fire watch on June 24,1992, when the sprinkler water for the component cooling water
and charging pump rooms was isolated by the operators for a work tag out. The error was caught six hours later apparently by the oncoming shift. During the six hour period, there was an hourly fire watch in the area as well as fire detection capability. The Licensee's action was appropriate and included adding fire watch considerations as the first step on tag out for.*s.
Q8.
What was the significance of these instances of missed fire watches and disabled fire barriers?
ANSWER (Miller) Each of the instances of missed fire watches and disabled fire barriers was of low safety significance. The Licensee continuously conducts an hourly roving fire watch that covers approximately ninety-five per cent (95%) of the safe shutdown areas of the plant and takes approximately forty-five (45) minutes to complete. This translates into over 8700 fire watches conducted each year. The instances of missed fire watches listed in Question Eight (8) represent a very low percentage of the total number of fire watches conducted. More importantly, the fire watches for Thermo-Lag represent a defense-in-depth approach, i.e., fire watches are in addition to existing detection and suppression systems. Additionally, none of the missed fire watches were associated with the compensatory measures the Licensee initiated as a result of the NRC's generic Thermo-Lag concerns. Indeed, in all of the other situations there was defense in depth.
Fire loading (combustibles) was low, and detection and suppression devices were I
. O available for most areas of concern. This defense in depth includes monitoring on each shift by operations personnel and hourly fire watches. Additionally, the impairments were either of short duration or, in the case of the fire damper, oflow safety significance, since that damper would have operated in the event of a fire because of the thermal actuation of its fusible link.
Q9.
Does that complete your testimony with regard to Thermo-12g and Fire Watches at Diablo Canyon?
ANSWTR (All) Yes.
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r PROFESSIONAL QUALIFICATIONS MARY H. MILLER ORGANIZATION:
Nuclear Regulatory Comission 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 Er.rineering 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 of the Senior.
Participated in the Diagncstic Evaluation Team inspection of the Fitzpatrick Nuclear Power Plant, and performed reactor start up operations inspections of the Trojan Nuclear Power Plant.
1989 - 1991 Nuclear Regulatory Comission, 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 cht.nges, 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.
1986 - 1988 Sagebrush Engineering.
o Founder, Owner and Operator Operated a home remodeling company. Designed home additions and repairs, supervised tradesmen and subcontractors, negotiated contracts.
4 1984 - 1987 Booz Allen and Hamilton Senior Engineer Primarily assisted Naval Sea Systems Command TRIDENT Submarine Program Office in areas of hull, mechanical, propulsion plant, and ship silencing concerns. Also assisted US Army 100 MW Reactor technical evaluation team, and other projects.
1982 - 1983 US Navy, Pittsburgh Naval Reactors Office, Pittsburgh, PA Naval Reactors Project Officer Inspected and audited the Bettis Westinghouse Atomic Power Laboratory for safety, technical and schedular compliance with Naval Reactors program.
Performed inspection in the areas of steam generators, valves, corrosion testing, and microanalytical analysis. The disciplines included chemical, mechanical, nuclear, materials, testing, and radiation protection.
1978 - 1982 US Navy, Naval Reactors Headquarters, Washington, DC Nuclear Power Project Officer Coordinated the Bettis Primary Components Program, steam generator design, inspection and maintenance, nuclear support facilities construction program.
Inspected Naval ship and shipyard reactor plant operations and refueling, i
and completed the Naval Reactor Design School.
Disciplines included heat transfer and fluid flow, physics, core design, shielding, quality assurance, testing, mechanical, chemical, electrical, structural and nuclear engineering.
AWARDS:
Received many awards from employers and civic organizations for outstanding performance.
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