ML20247R970

Safety Evaluation Supporting Amends 73 & 61 to Licenses NPF-10 & NPF-15,respectively

ML20247R970
Person / Time
Site:	San Onofre
Issue date:	05/31/1989
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20247R954	List: ML20247R947 ML20247R970
References
NUDOCS 8906080037
Download: ML20247R970 (10)

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NUCLEAR REGULATORY COMMISSION I

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.

TO FACILITY OPERATING LICENSE NO. NPF-10 3DAMENDftENTNO.

TO FACILITY.0PEFATING LICENSE NO. NPF-15 SOUTHERN CALIF 0khl A EDISON COMPANY SAN DIEGO GAS AhD ELECTRIC COMPANY THE CITY OF RIVERSIDE, CALIFORNIA THE CITY.0F ANAHEIM, CALIFORNIA SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2 AND 3 DOCKET h05. 50-361 AND 50-362 2.0 INTF,0 DUCT 10N By letters dated April 26, October 11, 6nd October 24, 1988 Southern Californic Edison Conpeny (SCE), et al., (the licensees) requesteo changes to the Technical Specifications for facility Optrating Literses No. NPF-10 anc ho. NPF-15 that authorize operation of San Onofre Nuclear Generhting Station (SONGS), Units 2 and 3 in San Diego County, California. These requests - designated as FCNs 247, 249, 257, 258, 261, and 265 - proposed to extend the interval for certain of the required 18 r.onth surveillance tests in order to support the nominal 24 month fuel cycle. Both Units 2 and 3 are operating in their first such cycle anc will te forced to shut cohn to perforrr, the 18 month surveillance unless the required interval is extended. SCE has submitted proposed changes to cover all the 18 mor.th surveillance tests which cannot be performed during plant operation. Many of these requests would have changed the required interval from "at least once every 18 months" to "et least once per refueling out6se." By letter dated March 20, 1989 SCE anended these requests to define " refueling outage' os 24 months. This cetinition would be included in the Freover.cy Hotetion table of the Techr.ic61 Specifications (Table 1.2) anc would upply to bil requestt containing such notation.

2.0 DISCUSSION AhD EVALUATION Definition of Refueling Interval By letter cated March 20, 1989 the licensees proposed to change Table 1.2 of Section 1.13, " Frequency Notation," of the SONGS Technical Specifications to 8906000037 890531 PDR ADDCK 05000361 P

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. add the term " Refueling Interval," which would be defined as "at least once per 24 months." SCE has confirmed that the " refueling interval" frequency notation is not now used in the Technical Specifications.

Because this change is administrative in nature and will have no effect on existing specifications, it is acceptable.

This change will apply to the pending requests to extend the 18 month surveillance intervals, and to any future requests containing a refueling interval frequency. A frequency of at least once per 24 months shall be l

l equivalent to at least once per 732 days. Surveillance Requirement 4.0.2 l

shall be applicable to the refueling interval unless the associated l

Limiting Condition for Operation specifically states that Specification 4.0.2 is not applicable.

The maximum allowable extension under Specifi-cation 4.0.2 shall not exceed 183 days. The maximum time interval for any 3 consecutive refueling interval surveillance shall not exceed 2379 days.

pCN-247 By letter dated April 26, 1988 the licensees proposed to change Technical Specification 3/4.6.4.2, " Electric Hydrogen Recombiners," to extend the 18 month surveillance interval to at least once per refueling outage (24 months).

This Specification requires two hydrogen recombiners to be operable during modes 1 and 2, defines periodic surveillance tests to verify operability, and specifies compensatory action to be taken when minimum operability requirements are not met.

The hydrogen recombiners are part of the post accident combustible gas control system.

During a postulated loss of coolant accident, hydrogen gas would evolve from the reaction of water with fuel cladding, radiolytic decomposition of water, and corrosion of metals inside containment. The function of the combustible gas control system is to maintain the' post accident concentration of hydrogen gas in the containment atmosphere below the limit of combustibility, thereby preventing hydrogen gas combustion from challenging containment integrity.

To verify operability of the hydrogen recombiners, Specification 3/4.6.4.2.a requires a functional test to be performed at least once per six months.

This test verifies that the minimum heater sheath temperature increases to greater than or equal to 700*F within 90 minutes and that, at 700*F and maximum power, the power meter indicates greater than or equal to 60 KW.

In addition, Specification 4.6.4.2.b requires each Hydrogen Recombiner System to be demonstrated operable at least once per 18 months by:

a)

Performing a channel calibration of all recombiner instrumentation and control circuits.

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Verifying through a visual examination that there is no evidence of abnormal conditions within the recombiner enclosure (i.e.,

loose wiring or structural connections, deposits of foreign material, etc.),and i

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Verifying the integrity of the heater electrical circuits by per-forming a resistance to ground test following the above required functional test. The resistance to ground for any heater phase i

shall be greater than or equal to 10,000 ohms.

l The hydrogen recombiners are located in the containment, so access to the

- containment is necessary to conduct the testing required by Specification 4.6.4.2.b.

To conduct this testing with the unit shutdown would decrease doses to the workers and help maintain radiation exposures as low as reasonably achievable. The recombiners are redundant, since only one is required to remove post loss-of-coolant accident (LOCA) hydrogen from the containment atmosphere. The recombiners themselves are of a-standard design, conforming to National Electric Code Standards with all components capable of sustaining accident environments. While the actual recombiner units are located inside the containment, their control panels are located in the control room and their power supplies are in the electrical pene-tration area adjacent to the containment building. These components will, therefore, not be exposed to the post accident environment.

Tests have verified that hydrogen-oxygen recombination is not a catalytic surface effect associated with the heaters, but occurs due to the increased temperature of the process gases. Therefore, saturation of the unit cannot occur, and deposits on the heater surfaces would not have a significant effect upon. recombination efficiency.

l SCE has examined the history of the 18 month surveillance tests of the hydrogen recombiners at SONGS Units 2 and 3 from the beginning of com-mercial operation to the present. All visual examinations have been satisfactory. The chsnnel calibrations have all been satisfactory except for one potentiometer on Unit 3 which required adjustment. The heater circuit tests have all been satisfactory except for one occasion when the heater leads were found reversed on a Unit 3 recombiner. This discrepancy 1

had no effect upon heater operation.

Based upon the nearly trouble-free performance of the 18 month surveillance tests and the capability of the functional test to provide assurance that the recombiners are operable, extension of the 18 month surveillance tests would not result in a significant reduction in hydrogen recombiner relia-bility. Any significant problems with channel calibration, loose connections, or heated electrical circuits would be expected to be detected during the semi-annual functional test. Foreign deposits on the heater surfaces would not significantly affect operability. Therefore, the staff concludes that the proposed change meets the intent of General Design Criteria (GDC) 42 and 43 and is acceptable.

PCN-249 By letter dated April 26, 1988 the licensees proposed to change Technical Specification 3/4.1.3.4, "CEA Drop Time," to extend the 18 month surveillance interval to at least once per refueling outage (24 months).

This Specification restricts the maximum allowable Control Element Assembly (CEA) drop time, as measured from the time that electrical power is

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~ interrupted to a fully withdrawn CEA drive mechanism to the time that the CEA i; 90% inserted. The maximum allowable CEA drop time is 3.2 seconds, which is consistent with the value assumed in the safety analysis. This Specification also defines the conditions which require demonstration of the drop time ano' specifies compensatory action to be taken when the minimum operability requirement is not met.

Surveillance Requirement 4.1.3.4. requires measurement of the drop time of full length CEAs prior to critic 6lity under the following conditions:

a. Following each removal and reinstallation of the reactor vessel head,

b. Following maintenance or modifications to the CEA drive system which could affect drop tines, and

c. At least once per 18 months.

Factors which could adversely affect the CEA drop times when the surveil-lanceintervalisincreasedare(1)changesincomponentclearances,(2) changes in the physical configuration of the CEA or guide tubes, and (3) the buildup of corrosion products and suspended material in the reactor coolant system that could interfere with CEA motion. SCE stated that changes to component clearances and changes in the physical configuration of the CEA or guice tubes are more likely to occur when the reactor vessel head is removed, and when maintenance is performed on the CEAs (including replacement) and that portion of the drive system directly interfacing with a fuel assembly. For these cases, Surveillance Requirements 4.1.3.4.a and 4.1.3.4.b, respectively, require CEA rod drop testing independent of the proposed change. SCE stated that chemistry requirements, as well as other controls on the reactor coolant system, will minimize corrosion anc build-up of corrosion products or other suspended materials in those areas which could affect CEA drop time.

In addition, each full length CEA not fully inserted shall be determined operable by movement of at least 5 inches in any one direction at least once per 31 days in accordance with Surveillance Requirement 4.1.3.1.2.

This surveillance requirement would detect CEAs that are sticking.

The staff has evaluated the licensees' submittal and has determined that those factors which affect CEA drop time are not time dependent to any significant extent. The surveillance requirements that are not affected by this change would be expected to identify any appreciable change in drop times. Based upon this assessment, the staff concludes that the l

proposed change is acceptable.

FCN-257 By letter dated October 11, 1968 the licensees proposed to change Technical Specifications 3/4.6.2.1, " Containment Spray System," and 3/4.6.2.3, "Contain-ment Cooling System," to extend the 18 month surveillance intervals to at least once per refueling outage (24 months). Specification 3/4.6.2.1 defines the required number of op(erable containment spray flow paths from the Re ing Water Storage Tanks surveillance tests to verify operability, and specifies compensatory action to 1-

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, l be taken when minimum operability requirements are not met. Specification 3/4.6.2.3 defines the required number of independent groups of containment cooling fans required to be operable, with two fan systems per group; defines periodic surveillance tests to verify operability; and specifies compensatory action to be taken when minimum operability requirements are not met.

l Operability of the Containment Spray System ensures that the containment l

depressurization and cooling capability will be available in the event of a LOCA. Surveillance Requirements 4.6.2.1.b.1, 4.6.2.1.b.2, and 4.6.2.1.b.3 require that each component in the Containment Spray System flow path be demonstrated operable at least once per 18 months by verifying that it actu-ates to its correct position upon a Containment Spray Actuation Signal (CSAS) test signal, a Recirculation Actuation Signal (RAS) test signal, and a Safety Injection Actuation Signal (SIAS) test signal, respectively. Specification 4.6.2.1.b.4 requires that each containment spray header riser be verified to be filled with water to within 10 feet of the lowest spray ring at least once every 18 months.

Operability of the Containment Cooling System ensures that the containment air temperature will be maintained within limits during operation, and that adequate heat removal capacity is available when operated in conjunction with the Containment Spray System during post-LOCA conditions. Surveillance Requirement 4.6.2.3.b requires each containment cooling fan group to be verified to start automatically on a Containment Cooling Actuation Signal (CCAS) test signal at least once every 18 months.

SCE states that Surveillance Requirements 4.6.2.1.b.1, 4.6.2.1.b.2, 4.6.2.1.b.3, and 4.6.2.3.b are met by testing all of the Engineered Safety Features Actuation System (ESFAS) relays in an actuation subsystem (e.g., CSAS) as a total unit.

The Plant Protection System (PPS) encompasses the Reactor Protective System (RPS) and the Engineered Safety Features Actuation System, including the electrical and mechanical devices and circuitry required to perform those functions. Surveillance Requirements 4.3.1.1 and 4.3.2.1 require periodic surveillance testing of the RPS and ESFAS instrumentation channels, respectively.

Table 4.3-2 of Specification 4.3.2.1 specifies monthly and semi-annual functional testing of the ESFAS instrumentation. SCE states that these requirements are satisfied by performance of the PPS Monthly Test and the Engineered Safety Features (ESF) Semi-annual Functional Test, which together test the ESF actuation logic from sensor inputs through actuation of the tested devices. Final Safety Analysis Report (FSAR) Section 7.3.1.1.1.9 describes a typical test program. The active logic components in the ESFAS actuation path are the PPS bistables, PPS matrix relays, PPS initiation relays, ESFAS subgroup relays, ESF motorcontrollers, and the ESF actuated devices. The PPS Monthly Test checks the PPS bistables, matrix relays, and initiation relays. The ESF Semi-annual Functional Test checks the ESFAS subgroup relays and motor controllers and actuates the device.

SCE states that the major difference between the combination of these two tests and the 18 month ESFAS test is that the latter tests all of the logic and actuated devices for a particular function at once. Components which cannot be tested during power operation are tested during the first cold shutdown longer than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if they have not been tested in the last

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. 1 6 months. SCE states that valves HV-9367, HV-9368, and HV-6501 are the only valves covered by Specification 4.6.2.1.b that cannot be tested at ower. Therefore, these valves might not be tested for up to 30 months p(24 months plus 25%). SCE has reviewed the test history of these valves and has determined that, during each of the past refueling cycle outages for both Units 2 and 3, these valves have passed their surveillance tests with no deficiencies. Each valve has also successfully passed two mid-cycle, semi-6nnual tests performeo while the unit was in a cold shutdown.

In addit-ion, Specification 4.0.5 requires inservice testing of all ASME Class 1, 2, and 3 pumps and valves in accordance with the ASME Boiler and Pressure Vessel Code. SCE has also reviewed the maintenance history for the compon-ents that cannot be tested at power. There was only one instance of corrective j

maintenance required for the components included in Specifications 4.6.2.1.b and 4.6.2.3.b.

Valve 2HV-9367 indicated 18% open when the valve was closed (November 1987).

This was found by Control Operators during routine operations.

Surveillance Requirement 4.6.2.1.b.4 requires verifying that each Containment Spray header riser is filled with water to within 10 feet of the lowest spray ring. This involves entry into containment and installation of test equipment and instrumentation. SCE states that, since the beginning of commercial operat% of Units 2 and 3, the results of this surveillance test have l

been satisfactory for both units.

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The staff has evaluated the licensees' submittal. We have determined that l

the monthly and semi-annual functional tests of the ESFAS channels provide sufficient assurance of Containment Spray System and Containment Cooling System response to ESFAS signals to allow extension of the 18 month surveillance interval to 24 months. In addition, the maintenance and test histories of those features which cannot be verified during power operation indicate that system reliability would not be significantly degraded by extension of the surveillance intervals. Therefore, the staff finds the l

proposed changes acceptable.

PCN-258 By letter dated October 24, 1968 the licensees proposed to change Technical Specification 3/4.6.3, " Containment Isolation Valves," to extend the 18 month surveillance interval to at least once per refueling outage (24 months). This Specification lists the containment isolation valves, specifies their required closure response times, defines periodic surveillance tests to verify operability, and specifies compensatory action to be taken when minimum operability requirements are not met.

Operability of the containment isolation valves ensures that the contain-ment atmosphere will be isolated from the outside environment in the event of a release of radioactive material to the containment atmosphere. Con-tainment isol6 tion within the time limits specified ensures that the re-lease of radioactive material to the environment will be consistent with the assumptions used in the safety analyses. Surveillance Requirement 4.6.3.2 requires that each isolation valve (except check valves) specified in Sections A and B of Table 3.6-1, " Containment Isolation Valves," be l

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v demonstrated operable at least once per 18 months by verifying that it actuates to its isolation position on an ESFAS test signal. SCE states that this requirement is met by testing all of the ESFAS relays in an actuation subsystem (e.g., CIAS) as a total un the Containment Purge Isolation System (CPIS) it, with the exception of valves which are tested separately.

As described under PCN-257 above, the PPS Monthly Test and the ESF Semi-annual Functional Test together test the ESF actuation logic from sensor inputs through actuation of the tested devices. Components which cannot be tested during plant operation are tested during the first cold shutdown longer than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if they have not been tested in the last 6 months.

SCE states that there are 13 containment isolation valves which cannot be tested at power. Therefore, these valves might not be tested for up to 30 months. SCE has. reviewed the test history of these valves and has determined that, during each of the past refueling outages for both Units 2 and'3, these valves have passed their' surveillance tests with no deficiencies. Each valve has also successfully passed 2 mid-cycle, semi-annual tests. In addition, Specification 4.0.5 requires inservice testing of all ASME Class 1, 2, and 3 valves in accordance with Section XI of the ASME Boiler and Pressure Vessel Code. SCE has also reviewed the maintenance history for components that cannot be tested at power and found that most problems were detected by operators during routine evolutions and on-line surveillance testing.

The staff has evaluated the licensees' submittal. We have determined that the monthly and semi-annual functional tests of the ESFAS channels provide I

sufficient assurance of containment isolation valve response to ESFAS signals to allow extension of the 18 month surveillance interval to 24 months. In addition, the maintenance and test histories of those features which cannot be verified during power operati:,n indicate that system reliability would not be significantly degraded by extension of the surveillance intervals. Therefore, the staff finds the proposed changes acceptable.

PCN-261 By letter dated October 24, 1988 the licensees proposed to change Technical Specifications 3/4.1.2.2, "Boration Systems, Flow Paths - Operating," and Greater Than or Equal to 350*F," to extend 3/4.5.2,"ECCS Subsystems - T@vals to at least once per refueling, outage the 18 month surveillance in (24 months). Specification 3.4.1.2.2 defines the boron injection flow paths to the Reactor Coolant System required to be operable, defines periodic surveillance tests to verify operability, and specifies compensa-tory action to be taken when minimum operability requirements are not met.

Specification 3/4.5.2 defines the rer,uired number of operable Emergency Core Cooling System (ECCS) subsystems, defines periodic surveillance tests to verify operability, and specifies compensatory action to be taken when minimum operability requirements are not met.

Operability of the Boration Systems ensures that negative reactivity control is available during each mode of reactor operation. Surveillance Requirement 4.1.2.2.c requires that each valve in the boron injection flow

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_ path be' demonstrated operable at least once per 18 months by verifying that it actuates to'its correct position upon a SIAS test signal.

t Operability of the ECCS subsystems ensures that sufficient emergency core cooling capability will be available in the event of a LOCA assuming the L

loss of one subsystem through any single failure. Surveillance Requirement 1

4.5.2.d.1 requires verifying the automatic isolation and interlock features of the Shutdown Cooling System (SDC) isolation valves.at least once per 18 months. Surveillance Requirement 4.5.2.d.2 requires a visual. inspection of the containment sump at least once per 18 months to verify that all sump inlets are free of debris and that no evidence of structural distress or abnormal conditions exist. Surveillance Requirement 4.5.2.e requires the components in the ECCS flow paths be demonstrated operable at least once per 18 months by verifying that they actuate to their correct position

.upon a SIAS test signal or a Recirculation Actuation Signal (RAS) test signal.

SCE states that Surveillance Requirements 4.1.2.2.c and 4.5.2.e are met by testing all of the ESFAS relays in an actuation subsystem (e.g., RAS) as a total unit.

As described under PCN-257 above, the PPS Monthly Test and the ESF Semi-annual Functional Test together test the ESF actuation logic from sensor inputs through actuation of the tested devices. Components which cannot be tested during plant operation are tested during the first cold shutdown longer than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if they have not been tested in the last 6 months.

SCE states that there are 3 boron injection flowpath valves and 8 ECCS subsystem valves which cannot be tested at power. Therefore, these valves might not be tested for up to 30 months. SCE has reviewed the test history of these valves and has determined that, during each of the past refueling outages for both Units 2 and 3, these valves have passed their surveillance tests with no deficiencies. Each valve has also successfully passed 2 mid-cycle, semi-annual tests. One other valve in the ECCS subsystem, which was recently modified to be an ESFAS actuated valve, cannot be tested at power and has passed all surveillance testing required by Specification 4.1.2.2.c.

In addition, Specification 4.0.5 requires inservice testing of all ASME Class 1, 2, and 3 valves in accordance with Section XI of the ASME Boiler and Pressure Vessel Code. SCE has also reviewed the maintenance history for components that cannot be tested at power and found that most problems were detected by operators during routine evolutions and on-line surveillance testing.

SCE has reviewed the test history under Specifications 4.5.2.d.1 and 4.5.2.d.2 from the start of commercial operation to the present and has found that all tests have been satisfactory.

The staff has evaluated the licensees' submittals. We have determined that the monthly and semi-annual functional tests of the ESFAS channels provide sufficient assurance of baron injection flowpath and ECCS subsystem valve response to ESFAS signals to allow extension of the 18 month surveillance

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_g interval to 24 rnonths. In aodition, the maintenance and test histories of those features which cannot be verified during power operation incicate that system reliability old not be significantly degraded by extension of the surveillance intervals. Therefore, the staff finds the proposed changes acceptable.

PCN-265 By letter cated October 11, 1988 the licensees proposed to change Technical Specification 3/4.5.1, " Safety Injection Tanks," to extend the 18 month surveillance interval to at least once per refueling outage (24 months). This Specification defines operability of the safety injection tanks (SITS); requires all tanks to be operable in modes 1, 2, and 3; defines periodic surveillance tests to verify operability; and specifies compensatory action to be taken when minimum operability requirements are not met.

Operability of the safety injection tanks ensures that innediate injection of the contents of the tanks will occur upon rapid loss of pressure in the Redctor Coolarzt System (RCS). During normal power operations the SIT isolation valves are required to be open with power removed. When operations require depressurization of the RCS, the valves are closed to prevent injection. If the valves are closed when RCS pressure rises above 715 psia or when an SIAS is received, the valves are required to open automatically.

Surveillance Requirement 4.5.1.e requires that each SIT isolation valve be verified to open before en actual or simulated RCS pressure signal exceeds 715 psia or upon receipt of an SIAS test signal.

SCE has reviewed the test history of Specification 4.5.1.e from the start of commercial operation to the present and has found that all tests have been satisfactory with only minor problems on two occasions.

The staff has evaluated the licensees' submittal. We have determined that, since the SIT isolation valves are only closed during non-power operations, performance of Surveillance Requirement 4.5.1.e shortly after the valves are closed provides sufficient assurance of valve operability to allow extension of the 18 month surveillance interval to 24 months. In addition, the test history of this surveillance indicates that system reliability would not be significantly degraded by extension of the surveillance interval. Therefore, the staff finds the proposed changes acceptable.

3.0 CONTACT WITH STATE OFFICIAL The NRC staff has advised the Chief of the Radiological Health Branch, State Department of Health Services, State of California, of the proposed determination of no significant hazards consideration. No comments were received.

4.0 ENVIRONMENTAL CONSIDERATION

The amendments involve changes in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 l

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' l and changes in surveillance requirements. The staff has determined that the amendments involve no significant increase in the amounts, and no l

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 Comission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been no public consnent on such finding.

f Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.

5.0 C0hCLUSI0h We have concluded, based on the considerations discussed above, that:

(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Comission's regulations and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor:

D. Hickman 1

Dated:

May 31, 1989 l

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