TXX-4392, Forwards Summary Description of balance-of-plant Mechanical Equipment Qualification Program.No Corrective Action Necessary as Result of Environ Qualification Study for safety-related Equipment in Potentially Harsh Environs

Forwards Summary Description of balance-of-plant Mechanical Equipment Qualification Program.No Corrective Action Necessary as Result of Environ Qualification Study for safety-related Equipment in Potentially Harsh Environs

ML20114A824
Person / Time
Site:	Comanche Peak
Issue date:	01/10/1985
From:	Beck J TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Youngblood B Office of Nuclear Reactor Regulation
References
TXX-4392, NUDOCS 8501280473
Download: ML20114A824 (9)

Text

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y' Log # TXX-4392 File # 10010 TEXAS UTILITIES GENERATING COMPANY 903.11 clo NKYWAY TOWER

• 400 N.)RTH .) LIVE NTREET. L.B. M1. DALLAN, TEXAN 75201 January 10, 1985 Director of Nuclear Reactor Regulation Attention: Mr. B. J. Youngblood, Chief Licensing Branch No.1 Division of Licensing U. S. Nuclear Regulatory Comission Washington, D.C. 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NOS. 50-445 AND 50-446 ENVIRONMFNTAL QUALIFICATION OF SAFETY RELATED MECHANICAL EQUIPMENT IN POTENTIALLY HARSH ENVIRONMENTS REF: (1) TXX-4233 of July 20, 1984

Dear Sir:

j In reference (1) a commitment was provided to perform and complete a study of the environmental qualification of safety related mechanical equipment in potentially harsh environments at CPSES. A description of the program 4

established to meet that commitment was attached to reference (1).

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The environmental qualification study for safety related mechanical equipment in potentially harsh environments at CPSES has been completed.

No corrective action was found necessary as a result of this study. No JI0s (Justifications for Interim Operation) are necessary as the environmental qualification of all the specified mechanical equipment was found to be adequate. Attachments 1 and 2 provide the final description of how the BOP and NSSS studies were performed.

Respectfully, A

DR 0 y O g, k ohn W. Beck DRW:grr Attachments Distribution: Original. plus 40 copies a

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ATTACHMENT 1 TO TXX-4392 SUMARY DESCRIPTION OF B0P MECHANICAL EQUIPMENT QUALIFICATION PROGRAM 1.0 PURPOSE The purpose of this program is to satisfy the requirement of the NRC staff that a study be performed to provide additional documentation to show that mechanical equipment at CPSES is adequately environmentally qualified (i.e., to show with adequate assurance that the mechanical equipment at CPSES will not suffer a common. mode failure-due to the environmental effects of a design basis accident that could jeopardize plant safety or the health and safety of the general public).

2.0 SCOPE The scope of this program is the safety-related Balance of Plant (BOP) nechanical equipment which must perform an active safety-related function following a design basis accident and which is located in a potentially harsh environment due to that accident.

Also included are containment and reactor coolant pressure boundary valves.

3.0 DEFINITIONS The following definitions are used in this program:

1 Accident = LOCA, Steam Line Break inside containment, Feed Line Break, HELB outside containment I

Safety-related B0P rechanical equipment = Safety Class 1, 2, or 3 equipment as defined by the CPSES design and described in the CPSES FSAR, excluding equipment purchased under the CP-0001 (NSSS) specification.

Active function = a function that requires the equipment to actuate or operate; that is, perform mechanical movement Potentially harsh environment = an environment which is significantly more severe than the environment that would occur during normal plant operation, including anticipated operational occurrences (based on the definition of mild environment in 10 CFR 50.49). Equipment was considered to be in a potentially harsh environment if the accident could cause the equipment to experience:

a. Exposure to chemical spray,

b. A rapid atmospheric pressure increase of 2 psi or more,

c. A rapid temperature increase to a temperature 50C or more above the maximum normal ambient including anticipated operational occurrences (or a peak above 1300F), or

d. A total integrated radiation exposure dose of 1x104 rads or more If only one of the two environmental parameters (radiation or temperature) exceeded its criterion for a harsh environment in a particular room, then the equipment in that room was evaluated only with respect to that parameter which has exceeded its harsh environment criterion.

Mechanical equipment is highly resistive to degradation due to evaluated humidity levels; therefore, relative humidity was not included as a parameter to be evaluated for environmental qual i fication.

4.0 QUALIFICATION METHODOLOGY The environmental qualification review of B0P mechanical equipment consisted of the following steps:

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a. Identification of mechanical equipment requiring evaluation

b. Identification of equipment location

c. Identification of nonmetallics for equipment

d. Identification of maximum postulated environmental conditions for the equipment locations

e. Identification of environmental effects on material properties

f. Thermal aging analysis for plastics and elastomers

g. Evaluation of environmental effects on equipment safety func tion The results of this evaluation are documented in a separate data package for each specification.

4.1 Identification of Mechanical Equipment Requiring Evaluation The initial step in determining the mechanical equipment required to be evaluated consisted of a review of specifications issued or revised as of May 1,1984.

The following categories of specifications were eliminated from the scope of mechanical equipment qualification:

a. Specifications which are not safety-related

b. Specifications which procure only electrical equipment

c. Specifications tAich procure only passive or structural equipment

d. Specifications which procure only equipment located in a non-harsh environment.

By elimination of specifications using this criteria, the list of specifications containing equipment within the scope of this procedure was determined. The equipment procured under each applicable specification is identified in each package.

The following examples of categorization of equipment results from application of the above criteria:

AC TIVE PASSIVE Pumps Piping / pipe supports Valves (which may be required to Fire stops and seals opera te) Venturies/ orifices Fans Cable trays & conduit Dampers Vent, drain and instrument Check valves root valves Safety a relief valves Terminal or junction boxes HVAC compressors Vessels, tanks, heat Hydraulic snubbers exchangers Containment hatches Expansion joints Reactor coolant and containment Strainers /fil ters pressure boundary valves Spool pieces / flanges (pressure boundary materials only) 4.2 Identification of Equipment Location The location of equipment requiring evaluation was determined and identified in each package. An exception is specifications (such as valve specifications) containing so many items that it would not be feasible to individually locate each one. This equipment is generically located in the plant's " worst case" location and evaluated on that basis.

4.3 Identification of Nonmetallic Subcomponents Manufacturer's bills of materials, vendor manuals, and vendor drawings for the equipment to be evaulated were reviewed. Where necessary, additional information was obtained from the equipment vendor to explain trade names, to identify specific trade name materials, or to clarify incomplete / unsatisfactory material identification. All nonmetallic subcomponents were identified and tabulated in each package, along with their material composition.

4.4 Identification of the Maximum Postulated Environmental Conditions for the Equipment locations The environnental conditions used for the review of mechanical i

equipment were based on the Interim Staff Position on Environmental Qualification of Safety Related Equipment, NUREG-0588, and radiation source terms were based on post-TMI values. These environnental conditions reflect the worst-case conditions to which equipment must be qualified.

4.5 Identification of Environmental Effects on Material Properties The consideration of pressure and chemical spray were evaluated generically to determine the potential impact on mechanical equipment. These parameters were addressed in each data package relative to the specific equipment.

Each nonmetallic was examined to determine the effect of the environnental conditions on the material properties. For each nonmetallic, a radiation threshold level and maximum service temperature were obtained. The radiation threshold level is the lowest radiation exposure at which property changes in the material is documented. The maximum service temperature is the maximum steady state temperature to which a material can be subjected without loss of function. The radiation threshold level and the maximum service temperature were obtained from the following:

materials handbooks, textbooks, government reports, laboratory data and industry sources. If the evaluation indicated that the lowest

. levels may_ be exceeded for certain equipment, higher levels were identified at which varying degrees of material degradation may occur.

4.6 Thermal Aging Analysis of Plastics and Elastomers Material aging analysis was completed for all plastics and elastomers. Mineral-based subcomponents were not considered to be sensitive to thermal aging during the design life of the plant and, therefore, were not analyzed. If the service life based on thermal aging was shorter than the planned maintenance interval, further evaluation was performed.

4.7 Evaluation of Environmental Effects on Equipment Safety Function A conservative initial screening of the nonmetallic subcomponents was made by comparison of the material capabilities (threshold radiation level and maximum service temperature) with the maximum postulated environmental conditions. If the threshold radiation values and the maximum service temperatures are above the maximum postulated environmental conditions and if the material aging analysis demonstrates a service life sufficient to survive the accident duration, then the material was considered acceptable.

Those items which were not shown to be acceptable based on the comparison were evaluated in further detail regarding:

a. degree of material degradation

b. material properties affected

c. equipment /subcomponent function

d. degree of equipment functional degradation

e. location specific environmental conditions If the subcomponent was shown to be acceptable by cvaluation, this evaluation was documented in the package.

If the subcomponent could not be shown to be acceptable by evaluation, then the equipment's ability to perform its intended safety function with respect to the subcomponent failure was evaluated and documented.

4.8 Acceptance Criteria In order to be considered acceptable, the nonmetallic subconponents of the mechanical equipment must:

a. be shown to be acceptaole for the plant environment by exhibiting threshold radiation values above the postulated environmental condition, and

b. be shown to be acceptable for the plant environment by exhibiting a maximum service temperature above the maximum postulated environmental condition, and

c. be shown to exhibit a service life sufficient to survive the accident duration, or

d. in lieu of a, b, and c above, be shown to be acceptable for the plant environment by analysis that demonstrates that the safety function of the component is not conpromised.

The mechanical equipment was considered qualified if all subcomponents were shown to be acceptable. If any subcomponent was not shown to be acceptable by either comparison or evaluation for the postulated plant environment, then the equipment was identified as requiring further evaluation.

5.0 CONCLUSION

The study has been completed and the required data packages have been prepared, reviewed and accepted. All the equipment within the scope of this study was found acceptable. No problems were

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identified as a result of this study that required corrective action (e.g., equipment or material replacement) before the equipment could be accepted. The data packages have been incorporated into the auditable files for the Comanche Peak Steam Electric Station.

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