ML16340A908

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Affidavit Demonstrating That Independent Review of Safety Related Equipment Qualification Program Should Be Conducted Prior to OL Issuance
ML16340A908
Person / Time
Site: Diablo Canyon  Pacific Gas & Electric icon.png
Issue date: 02/28/1980
From: Hubbard R
MHB TECHNICAL ASSOCIATES
To:
Shared Package
ML16340A907 List:
References
NUDOCS 8004210393
Download: ML16340A908 (26)
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Text

UNITED STATES OF- AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In The Matter Of: )

)

PACIFIC GAS AND ELECTRIC COMPANY )

) Docket Nos. 50-275(OL)

(Diablo Canyon Nuclear Power ) 50-323(OL)

Plant Units 1 and 2 )

AFFIDAVIT OF RICHARD BURTON HUBBARD STATE OF CALIFORNIA )

) ss.

COUNTY OF SANTA CLARA )

RICHARD B. HUBBARD, being of legal age and duly sworn, deposes and says as follows:

1. I am a Profes'si,onal Quality Engineex, technical con-sultant, and a founder and partner of MHB Technical, Associates, technical consultants on energy and environment, with offices at 1723 Hamilton Avenue, Suite K, San Jose, California. I have participated as an expert witness in licensing proceedings befoxe U.S. 'Nuclear Regulatory Commission (NRC) including the Diablo

'he Canyon seismic hearings; have testified at the request of the NRC's

Advisory Committee on Reactor Safeguards; have appeared before various committees of the U.S. Congress; and have testified in various state licensing and regulatory proceedings. I am familiar with the design verification and equipment qualifica-tion program of the Diablo Canyon license Applicant (Pacific Gas and Electric Company) and the Nuclear Steam Supply System supplier (Westinghouse) as a result of my service as a consul-tant since the fall of 1976 to the Center for Law in the Public Interest, attorneys for the Joint Intervenors in the Diablo Canyon Operating License proceeding'. I received a B.S. in electrical engineering from the University of Arizona in 1960 and an NBA from the University of Santa Clara in 1969. From 1964 to February 1976 I was employed in the Nuclear Power Divi-sion of the General Electric Company, with the final eleven of the twelve years working in increasingly responsible management positions.. While employed by General Electric, I participated in the classification o'f safety-related equipment to be qualified and the review of the eventual qualification program. My quali-fications and experience are described in detail in the testimony I presented during the Diablo Canyon seismic hearings in 1979.

In addition, in 1979, I performed, along with my two partners, a major study for the U.S. Department of Energy, through the Sandia Laboratory,, to evaluate and recommend changes to bring about improvement in LWR safety. The results of this study are docu-mented in a report entitled, "Improving the Safety of LWR Power

Plants" issued by MHB in September, 1979. At the. present time, I am actively working on nuclear asses"sments 'under contracts with.

(a) the Swedish Nuclear Inspectorate on evaluation of pipe cracks, risk assess-ment uncertainty, and safety of older nuclear plants; (b) the state of Minnesota Pollution Control Agency on development of a plan to study the safety of two nuclear plants in Minnesota (Monticello and Prairie Island);

(c) the Oklahoma Attorney General's Office on evaluation of safety issues at the proposed Black Fox plant.

2. The purpose of this affidavit is to discuss new factors pertinent to the Diablo Canyon Station that demonstrate the need for additional review of the environmental qualification of the safety-related structures,. systems, and components. My affidavit demonstrates that the information on the qualification

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program for safety-related items should include (a) an identifi-cation of all Diablo Canyon Class I safety-related equipment and (b) an evaluation of aging effects on the qualification of all Diablo Canyon Class I safety-related equipment. Further, an independent review of the specific details of the environmental qualification program, prior to the issuance of the Diablo Canyon, operating license, is necessary to demonstrate that theDiablo Canyon Station can operate without undue risk to the health 'and safety of the public.

3. A nuclear reactor is licensed on the basis of a safety evaluation whi'ch "includes'he 'systems and components installed to prevent accidents from releasing radiation and endangering the health and safety of the public. Nuclear plants such as Diablo Canyon, are described as having a 40-year pro-jected lifetime which is generally determined by the wearing out of some of the vital components and systems to the point where safe operation cannot be assured. It is this process of wearing out that this affidavit addresses; specifically the effects of aging on the safety of reactor operation. As it will be used here, aging will be defined as it is in U.S. standards:

"AGING. The cumulative effect of operating ". ".

~cyc es and'nvironmental and system conditions imposed on the equipment during a period of service.'

I The result of aging may be the degradation of a component or system's capability to perform its desired function. When the desired function is related to the safety of reactor operation or accident mitigation, these concerns are particularly imp or tant.

  • IEEE Draft Standard 7627, "Standard for Des'ign Qualification of Safety-Related Equipment Used in Nuclear Power'ener'ating Stati.ons," Draft 3, June '7, 1977.
4. There are three phases or periods of equipment failures; (a) infant or break-in failures', (b) normal or random failures, and (c) wear-out or old-age 'failures. This is shown graphically in Figure l.

FIGURE 1 FAILURE RATES versus TIME l

Failure I Random Rate Break,I" Near-In Out Time This 'curve is often refeixed to as the "bathtub curve" because of its shape. Hopefully, most of the break-in failures will be found in. the factory before the equipment is in reactor operation. Unfortunately, this is not always the case. The time defined as the random failure period corresponds to the design life and is where one would like equipment to operate

during':the life of the'eactor.

  • However, such is -not the case since many components cannot be -des'igned to run for'40 years in a severe environment. Thus, -reactors. can and do have components in each of the three periods of the bathtub curve at any given time.
5. There are a number of factors which contribute to aging, including the environmental factors of temperature, pressure, humidity, chemicals, and radiation. These factors, along with 'life expectancy, must be considered in designing reactor components. If equipment cannot meet the required life, it may be designed to be replaceable.
6. Requirements for environmental qualification of safety-related equipmemt have been evolving as a result of efforts expended by both the NRC and nuclear industry. As a result of these efforts, the NRC has developed an interim posi-:

tion regarding environmental qualifications. For. example, the new NRC requirements for the qualification of Class IE

  • The installed life may differ from the design life which may in turn differ from the qualified life for a given system.

These are defined as:

Installed Life: The interval from installation to removal.

Design Life: The time during which 'satisfactory perfor-mance can be expected fox a specific set of service conditions.

Qualified Life: The period of time 'in which satisfactory performance 'can be demonstrated. .The qualified life should exceed thedes'ign life.

For fux'ther discussion of this point, the reader is referred to Nuclear Safet , Vol. 18, No. 3, May-June 1977, pp. 317-321.

instrumentation and electrical equipment at Diablo Canyon was provided to Pacific Gas and Elec'tric Company in a letter dated November 2, 1979 (see Attachment A).

7. In the November 2, 1979 letter, the NRC specifically noted that the listing of equipment in the Diablo Canyon FSAR was insufficient as follows:

"The FSAR Tables that identify the operational requirements of equipment which must function during and subsequent to the design basis acci-dents are general and are not sufficiently complete for purposes of documenting equipment qualification parameters. Therefore, provide a table listing of all Class IE safety-related equipment and appropriate qualification related data for each as noted in the attachments This table should include all equipment located both inside and outside of containment, including balance-of-plant and nuclear steam system supplied equipment."

8. Futher new guidance on equipment qualification of safety-related electrical equipment was provided by the NRC to Pacific Gas and Electric Company in a letter dated February 5, 1980 (see Attachment B) . In addition, NUREG-0588, dated Decem-ber 1979, which was enclosed with the February 5, 1980 letter, elaborated on the new NRC requirements for plants such as the Diablo Canyon Station that are in the operating license review process.

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9. The following new'nformation concerning identi-fication of Class 1E equipment to be environmentally qualified was described in part by the HRC in Appendix E of NUREG-0588 as follows:

"In order to ensure that your environmental qualification piogram conforms with General Design Criteria 1, 2, 4 and 23'f Appendix A and Sections CFR III and XI, of Appendix B to 10 Part 50, and to the national standards mentioned in Part II 'Acceptance includes IEEE Std. 323) contained in Criteria'which Standard Review Plan Section 3.11, the following information on the qualification program is required for all Class IE equip-ment.

1. Identify all Class IE equipment, and provide the following:
a. Type. (functional designation)
b. Manufacturer
c. Manufacturer's type number and model number
d. The equipment should include the following, as applicable:

(1) Switchgear (2) Motor control centers (3) Valve operators (4) Motors (5) Logic equipment (6) Cable (7) Diesel generator control equipment (8) Sensors (pressure, pressure differential, temperature and neutron)

(9) Limit switches (10) Heaters (11) Fans (12) Control boards (13) Instrument racks and panels (14) Connectors (15) Electrical penetrations

-(16) Splices (17) Terminal blocks" As discussed in Item 7, such a detailed listing is not presently contained in the Diablo Canyon FSAR.

10. In the November 2, 1979 letter, the NRC also requested additional information from Pacific Gas and Electric Company which addresses aging mechanisms as follows:

"IEEE std. 323-1971 does not specifically address aging mechanisms as a consideration in the quali-fication of safety related electrical equipment.

Subsequently, IEEE Std. 323-1974 addressed aging in the sequence of factors to be considered. While for many components, aging may not play ato-signifi-cant role in the ability of a component withstand the effects of an abnormal or accident environment and still perform its required function; there are certain materials which may be subjected to degra-dation over a long period of time. It is the staff's position that applicants, with qualification programs

'nfor safe'ty-related electrical equipment, conducted accordance with IEEE Std. 323-1971, should under-take an investigation of the electrical equipment to ensure that significant aging mechanisms- do not exist which could invalidate the conclusions of prior qualification, Sources of information, specifically material manufactureres data, should be consulted as a part of this review. Therefore, you are requested to conduct such an evaluation .

and to report your findings at the earliest oppor-tunity. For any equipment for which significant aging mechanisms are identified, provide the justi-fication and time interval for acceptable use of this equipment which does not invalidate its prior qualification or provide other proposed alternatives such as requalification or replacement with qualified equipment and not subject to aging concerns."

11. The NRC in NUREG-0588, pages 15 and 16 (see Attachment C), provided Pacific Gas and Electric Company with additional new information describing, the new NRC position on the considera-tion of aging in the qualification of safety-related electrical equipment. However, as discussed in this and Item 10, the detailed submittals on aging are not yet included in the Diablo Canyon

FSAR and the NRC's detailed review'of aging is not yet included in a,supplement to the Diablo Canyon =SER.

12. The NRC interim position. on, equipment qualification, as described in NUREG-0588, may change further -in the future as acknowl'edged by, the NRC in the following statement:

"These positions, whi.ch are presented in this report, provide guidance on the establishment of service conditions, methods for qualifying equipment, and other related matters. They do not address in detail all areas,.of qualifica-.

tion, since certain areas are not yet well under-stood and are the subjects, of research studies conducted by the NRC and by the industry. For example, the effects-.of- aging, sequential versus simultaneous, testing, including synergistic effects, and the potential combustible gas and chloride formation in equipment containing, organic materials are being evaluated.'t is expected that these studies will lead to the

'development of more detailed guidance in the future, and may require changes to these positions." *

13. Safety evaluations are based on a single-failure analysis assuming 'another component or system is inoperative or bypassed. Single-failure is only valid if there are no mecha-nisms for causing multiple pieces of redundant equipment to fail simultaneously. Aging has the ability to pxoduce such an effect.

Be it weakened insulation, neutron embrittled steel, component material change, or light bulbs burning out due to over voltage, there are numerous failures which could impact several redundant

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components which have been aged. Multiple failures of critical components can be a serious threat to safety, particularly for a plant like Diablo Canyon which is located in a region of high seismicity. Therefore, aging may -erode the design/safety margins assumed in the licensing process. This is said very clearly in the IEEE draft standard on qualification (including aging):

"Inherent to any safety analysis are two pre-sumptions which must be tested to assure overall technical validity. First, designs must be such that. equipment is capable of performing its designated safety functions in associated design basis event environments. Second, in-service wear and a'ging must not degrade safety-related equipment from its original design "condition to the point where safety function it to cannot per'form its required a design basis event =environ-ment.

The special environmental conditions associated with some design basis events promote the possi-bility that production testing, normal s'ervice surveillance testing, and may not be able to determine if the equipment is .vulnerable'o failure, either as a result of inadequat.e design or aging or wear. Under these circumstances, redundant safety-related equipment failures might occur just at the time safety functions are required. It is the fundament'al role of quali-fication to provide assurance that design exist."

and age related common failure modes may not

14. The foregoing discussion demonstrates that a detailed independent review of the qualification program for safety-related equipment should be conducted prior to the issuance of the 'Diablo Canyon operating license. In summary, my investigations indicate

that the lists of Category I, structures-, systems, and components provided to assure (a) the integrity of the reactor coolant boundary, and (b) the capability to shut down the reactor and maintain it in a safety condition are general and are not sufficiently complete for purposes of documenting equipment qualification parameters. Further, my. investigations indicate that the effects of aging have not been properly considered in the seismic and environmental qualification of safety-related equipment.

15. All of the matters herein are known to me of qy personal knowledge or of my personal opinion based on my educa-tion and experience. If called as a witness, I am competent and would testify thereto.

RICHARD B ..HUBBARD Subscribed and sworn to before me this 4 Z 4~ day o f February, 1980 (cr<. t ~ < ~ i f /<~~0 NOTARY PUBLIC Ny commission expires: g. ~ii .<.< f . IHV d

OFF<t,w ouq KAREN L ENGE1S Notary Public Cali fornia Principal Offfce in Santa Qara County My commission expires lan. 13, 1984

ATTACHMENT: DES'CRXPTION Letter', Stolz 'to Morrissey, dated November 2, 1979 entitled, "Environmental Qualification of Class IE Instrumentation and Electrical Equipment (Diablo Canyon, Units 1 and 2)."

. Letter, Ross to All Construction Permit and Operating License Applicants, dated February 5, 1980 entitled, "Issuance of NUREG-0588,

'Interim Staff Position on Equipment Qualifi-cation of Safety-Related Electrical Equipment."

C NUREG-0588, pages 15 and 16.

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