ML20205Q977

Safety Evaluation Supporting Amend 3 to License NPF-58

ML20205Q977
Person / Time
Site:	Perry
Issue date:	04/01/1987
From:	Office of Nuclear Reactor Regulation
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Shared Package
ML20205Q946	List: ML20205Q941 ML20205Q970 ML20205Q977
References
NUDOCS 8704060152
Download: ML20205Q977 (5)

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~g UNITED STATES 8 o NUCLEAR REGULATORY COMMISSION h  : WASHINGTON D. C. 205S5

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 3 TO FACILITY OPERATING LICENSE NO. NPF-58 CLEVELAND ELECTRIC ILLUMINATING COMPANY, ET AL PERRY NUCLEAR POWER PLANT, UNIT NO. 1 DOCKET NO. 50-440 I.0 INTRODUCTION By letter dated March 4,1987, as supplemented on March 19, 1987, Cleveland Electric Illuminating Company, Duquesne Light Company, Ohio Edison Company, PennsylvaniaPowerCompany,andToledoEdisonCompany,(thelicensees) requested an amendment to Facility Operating License No NPF-58 for the Perry Nuclear Power Plant, Unit No. 1. The proposed amendment would change the maximum isolation time allowed by the Technical Specifications from 50 seconds to 20 seconds for operation of the Reactor Core Isolation Cooling (RCIC) system inboard containment isolation valve (IE51-F063). This change was requested in relation to a planned conversion of this normally-closed valve, which is presently operated by a direct-current (DC) motor operator, to be normally-open with a more reliable alternating-current (AC) motor operator. The amendment would also delete from the Technical Specifications the load represented by the DC motor operator on the valve and the identification of the motor control center through which DC power is supplied to the motor operator. The replacement AC supply will be from another motor control center which is presently identified in the Technical Specifications.

2.0 EVALUATION

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The purpose of the RCIC system is to provide reactor coolant makeup when the reactor pressure vessel is isolated but still at high pressure. The F063 valve serves as the inboard isolation valve in the line which provides steam to operate the RCIC turbine. This valve was installed with a DC powered operator to assure that the RCIC system can operate independent of any normal or emergency AC power and the valve is kept normally closed to  !

provide maximum assurance of containment isolation in the event of a break

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in the RCIC steam line outside containment. j CEI is proposing to modify the present arrangement because operability tests have shown that the DC motor operator is unreliable and attempts to correct this problem have been unsuccessful. Changing the power source for the motor operator to AC would facilitate replacement of the motor operator with another component which is already qualified for service inside the drywell. The power supply will be Class 1E. The addition of the valve motor operator to the Division 2 AC system would have only a minor impact I on system loading.

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l The second change is that the valve will now be normally open; this is l necessary to meet the design requirement that RCIC be operable independent of AC power. The isolation function (which need not be independent of AC  ;

power) will be provided automatically upon receipt of a signal indicating a break in the RCIC steam line, i The F053 valve is designed to close in less than 20 seconds after receipt of an isolation signal. . The licensee has reported that the dose consequences for a break in the RCIC line with a 20-second isolation valve closure time are bounded by the existing steam line break analysis. Since the RCIC stean line flow area is about a factor of 20 smaller than the main steam line flow area and the RCIC isolation valve closure time is only a factor of 4 larger than the MSIV closure time, the staff agrees that the dose consequences are bounded. The licensee has also stated that safety equipment in rooms where reactor coolant could be released under accident conditions is qualified for the environment resulting from a break with isolation in 20 seconds.

The staff questioned CEI as to the reliability of the F063 valve under flow conditions expected during a break in the RCIC steam line. The licensee indicated that the valve is designed to operate against the maximum calculated system pressure. However, the valve has not actually been tested under flow conditions which could occur in the event of a line break. As a consequence, the licensee has committed to further evaluate the proposed design configuration, as well as alternative configurations, to determine the most desirable desion. The evaluation will take into

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account both system availability and isolation capability. CEI bas committed to provide the results of the evaluation to the staff by December 31, 1987.

By October 31, 1987 CEI will provide to the staff a summary of the alternative configurations being considered. Prior to startup following the first refueling outage, CEI will implement the appropriate modifications,-

if required by the staff.

The staff considers the licensees' commitments sufficient to address the concern regarding isolation valve operability. We also note that this issue is currently being pursued by the staff as Generic Issue 87:

" Failure of HPCI Steam Line Without Isolation." Operation until the first refueling outage is considered acceptable since the Perry Plant equipment layout is such that it is unlikely that more than one emergency core cooling (ECC) subsystem could be affected by a break in the RCIC steam line. Different ECC subsystems are in different equipment rooms separated by physical barriers so that environmental disturbances (such as pipe rupture) in one system will not affect the remaining subsystems. Any one water injection subsystem of the ECCS has sufficient capacity for main-taining the core covered after a RCIC steam line break. Therefore, significant fuel failures would not be expected for this event.

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3.0 EXIGENT CIRCUMSTANCES

Due to several instances in which the RCIC system inboard containment isolation valve had failed to open during tests, CEI informed the NRC, in a letter dated February 24, 1987, of its-intent to make physical changes to the motor operator on the valve. In order to complete Startup Test Condition 1 prior to making such changes, CEI requested and was granted interim relief for a period of 30 days from the requirement that this normally-closed valve be operable (letter from Robert H. Bernero, NRC, to Murray R. Edelman, CEI, February 24,1987).

Subsequently, CEI decided to replace the existing DC motor operator on i .the valve.with an AC motor operator and to modify the position of the valve to normally open. These modifications involve changes in the

! Technical Specifications, which were requested by the licensees by a letter on March 4, 1987. Since the changes are necessary to allow operation of the plant beyond March 26, 1987, there was insufficient time to process this amendment in the normal manner, which allows 30 days for public comment following publication of a notice of the proposed action in the Federal Recister. However, there was sufficient time for a two-week comment period. Therefore, CEI requested that this amendment be processed under exigent circumstances, in accordance with 10 CFR 50.91(a)(6).

The staff has reviewed the circumstances associated with the licensees' request and agrees that the amendment is necessary for continuation of startup testing and that failure to act upon the request in a timely manner would prevent resumption of plant operation. The staff concluded that this situation could not have been avoided and, therefore, valid c exigent circumstances exist, as defined by 10 CFR 50.91(a)(6).

3.1 FINAL NO SIGNIFICANT HAZARDS CONSIDFRATION DETERMINATION The Comission has provided standards for determining whether a

, significant hazards consideration exists as stated in:10 CFR 50.92. A proposed amendment to an operating license for a facility involves no significant hazards considerations if operation of the facility in

accordance with a proposed amendment would not: (1) involve a j' significant increase in the probability or consequences 'of an accident previously evaluated; or (2) create the possibility of a new or

different kind of accident from any accident previously evaluated; or j

(3) involve a significant reduction in a margin of safety.

ihe licensee has provided an analysis of its proposed amendment request

. in relation to the above standards and has concluded that it involves no

significant hazards considerations. The Connission also has made a final i

detemination that the amendment request involves no significant hazards considerations, based on the above standards and the following considerations:

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l The-proposed change does not involve a significant increase in the probability or consequences of an accident previously analyzed because the change from a DC motor operator to an AC motor operator and the decrease in the operating time requirement from 50 seconds to 20 seconds will serve to increase rather than decrease the availability of the RCIC system and the operation of the RCIC s / stem with the valve normally open, but able to close within 20 seconds, is within the bounds of the existing main steam line break analysis. For environmental qualification, the licensees have performed an analysis which demonstrates that line isolation within 20 seconds will not jeopardize equipment required for safe shutdown r in the environmental zones (pressure, temperature, humidity) related to the ,

postulated pipe break. i The proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated because the RCIC system reliability will be increased, the RCIC system operation will remain within the bounds of existing safety analyses, and the basic operation of ,

the RCIC system will not change. Furthermore, the change from DC to AC e operation will not significantly affect either the AC or DC power systems, as the AC power has more than sufficient capacity to supply the increased load of the valve operation and the load on the DC power system will decrease.

The proposed change does not involve a significant reduction in a margin of safety because the basic operation of the RCIC system is not changed, the isolation valve will maintain all of its present isolation signals, and it will be capable of operating against the maximum calculated system pressure while satisfying all applicable General Design Criteria of Appendix A to 10 CFR Part 50. As indicated in the staff's evaluation (Section 2.0 above), the F063 valve has not actually been tested under flow conditions which could occur in the event of a RCIC steam line break downstream. However, it is unlikely that more than one ECC subsystem could be affected by a RCIC steam line break and any one of the ECC water injection subsystems has sufficient capacity for keeping the reactor core covered after such a break.

Accordingly, the amendment does not involve significant hazards considerations.

3.2 JTATECONSULTATION The staff consulted with the State of Ohio by telephone on March 26, 1987. There were no comments on this amendment.

4.0 ENVIRONMENTAL CONSIDERATION

l This amendment involves a change to a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes to the surveillance require-ments. The staff has determined that the amendment involve's' no significant

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• O increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure.

The Commission previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pur-suant to 10 CFR 51.22(b), no environmental impact statement nor environ-mental assessment need be prepared in connection with the issuance of this amendment.

5.0 CONCLUSION

The staff has concluded, based on the considerations discussed above, that: (1) the amendment does not (a) significantly increase the probability or consequences of an accident previously evaluated, (b) create the possibility of a new or different kind of accident from any previously evaluated, or (c) significantly reduce a safety margin and, therefore, the amendment does not involve significant hazards consider-atians; (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner; and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.

Prinicipal Contributors:

T. Collins and P. Leech Dated: April 1, 1987 t