ML20235S495
| ML20235S495 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 09/29/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20235S485 | List: |
| References | |
| NUDOCS 8710090021 | |
| Download: ML20235S495 (19) | |
Text
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UNITED STATES
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g NUCLEAR REGULATORY COMMISS!ON qj WASHINGTON, D. C. 20555 a
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING EXEMPTIONS FROM THE REQUIREMENTS OF APPENDIX J CONNECTICUT YANKEE ATOMIC POWER-COMPANY 1
HADDAM NECK PLANT DOCKET N0. 50-213
1.0 INTRODUCTION
By letter dated March 12, 1986, Connecticut Yankee Atomic Power Company (CYAPC0), the licensee for the Haddam Neck Plant, requested exemptions from the requirements of Appendix J.
The exemptions were requested with the intent of performing detailed evaluations and scheduling the modifica-tions required as part of the Haddam Neck Plant Integrated Safety Assessment Program (ISAP).
CYAPC0 proposes to integrate the required Appendix J
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modifications with other regulatory requirements and utility initiated 1
I projects in ISAP to establish priorities for the various items and schedule the implementation of each item.
By letter dated July 15, 1986, CYAPC0 forwarded a revised exemption l
request. The revision a ed two valves to the earlier request.
Additionally, by letter cated July 16, 1986, CYAPC0 proposed several modifications for the 1987 outage. These modifications were based on a probabilistic analysis and a review of their Type A and C leakage history.
These modifications will be performed independent of the Haddam Neck integrated assessment.
By letter dated June 10, 1987 CYAPC0 withdrew its request for exemption to perform containment integrated leak rate testing at the reduced pressure of 15 psig.
2.0 PERMANENT EXEMPTIONS EVALUATIONS The staff has reviewed the above documents to determine the acceptability of the exemption requests. Our evaluation of each exemption follows.
2.1 Exemption Requested Section II.H of 10 CFR Part 50, Appendix J requires that Type C tests be performed for containment isolation valves that:
1.
Provide a direct connection between the inside and outside atmospheres of the primary reactor containment under normal operation, such as purge and ventilation, vacuum relief, and instrument valves; B710090021 070929 ADOCK050g3 PDR P
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2 2.
Are required to close automatically upon receipt of a containment isolation signal in response to controls intended to effect containment isolation; 3.
Are required to operate intermittently under post-accident conditions; and 4.
Are in main steam and feedwater piping and other j
systems which penetrate containment of direct-cycle boiling water power reactors.
CYAPC0 requests exemption from the Type C testing requirements of Section II.H of Append'.x J for the steam generator blowdown (P-15, 16, 17, 18),
and auxiliary feedwater (P-81) penetrations.
l Licensee BasisSection II.H.4 of Appendix J does not require that the main steam and feedwater systems in PWRs be Type C tested.
These systems are not directly connected to the reactor coolant system and are not postulated to rupture as a result of a loss-of-coolant accident (LOCA). Consequently, these systems do not experience post-LOCA leakage of containment atmo-sphere. Further, CYAPC0 has implemented post-accident emergency procedures to maintain steam generator water level above the tube bundle and to pres-surize the secondary side to a pressure greater than Pa as soon as practi-i cable following the onset of a postulated LOCA. The steam generator blowdown (P-15, 16, 17, and 18) and auxiliary feedwater (P-81) penetrations are not connected to the reactor coolant system and are not relied upon to prevent the escape of containment air following a postulated LOCA. Con-sistent with the application of Section II.H.4 to the main steam and feed-water penetrations (P-42 through 49) at the Haddam Neck Plant, CYAPC0 maintains that the steam generator blowdown and auxiliary feedwater penetrations should be permanently exempt from Type C testing.
Evaluation By letter dated May 7, 1982, the staff concluded that Appendix J,Section II.H does not require these valves to be leak tested, therefore, no exemption is necessary. The staff's original conclusion was based on I
the fact that this is a seismically designed, closed system and these penetrations would not be a potential containment leakage path. Addi-tionally, CYAPC0 has agreed to maintain steam generator water above the tube bundle and pressurize the secondary side above Pa as soon as possible following the onset of a postulated LOCA.
Conclusion As the basis for the original conclusion is unchanged, the staff does not require an exemption for these valves and Appendix J does not require them to be leak tested.
2.2 Exemption Requested Section III.C.1 of Appendix J to 10 CFR Part 50 states:
" Type C tests shall be performed by local pressurization.- The pressure shall be applied in the same direction as that when the valve would be required to perform its safety function, unless it can be determined that the results from the tests for a pressure applied in a different direction will provide equivalent or more conservative results...."
CYAPC0 requests an exemption from the above requirment so that valves in the auxiliary spray penetration (P-80)~may be tested.in the. reverse direction.
Licensee Basis The containment spray (P-80) penetration is isolated by motor-operated valve RH-MOV-31, which is tested in the reverse direction.
Piping-associated with this penetration is pressurized by the fire water mstem at a minimum pressure of 80 psig. The fire water system uses the-Connecticut River as its source of water; and the system pumps have a capacity of 2900 gpm at 100 psig. The system is comprised of an electric driven pump with a backup diesel driven pump; the status of the pumps is provided in the control room, and the pumps may be operated.from the control room. The fire water system is maintained in accordance with the quality assurance requirements of the fire protection program. System pressure is normally controlled at 100 to 110 psig by a hydropneumatic pressure maintenance system.
While the yard piping loop is a single line, sectionalizing valves are provided to permit partial line isolation without interruption.of service to the entire system. Thus, a pressure at least double accident pressure (Pa) is reliably maintained in this piping, which would assure that the valves in this penetration are not exposed to containment atmosphere leakage. Although this penetration is not sealed by an installed seal system, the penetration is effectively sealed by the system itself, and water testing of this penetration at a pressure not less than 1.1 Pa is appropriate.
Further, reverse direction testing of this penetration is appropriate since post-accident leakage would tend to occur into the containment. On this basis, CYAPC0 believes that a permanent exemption from the requirements of Appendix J to permit reverse direction testing of Penetration P-80 is justified.
Evaluation l
The auxiliary containment-spray penetration (P-80) is isolated by motor-operated valve RH-MOV-31, which is currently Type C tested in the reverse direction with water. During the ILRT the system outside containment is pressurized by the fire water system at a minimum of 80 psig assuring that there will be no leakage out of containment through this penetration. The
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licensee has argued that since the fire water system is maintained at least at 80 psig by an electric driven pump with a diesel driven backup their current testing meets the underlying purpose of the rule. The NRC staff concluded that the above leak testing for this penetration would be in compliance with Ap-
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pendix J if CYAPC0 could demonstrate an effective 30 day water seal at a pres-i sure of at least 1.1 Pa, in accordance with Sections III.C.2(b) and III.C.3(b) of Appendix J.
This would require that the fire system satisfy the requirements for a safety grade system (i.e., a code class system, seismically qualified, l
with emergency power and capable of functioning with a limiting active single j
failure).
However, this system does not meet several of these requirements; therefore, an exemption is required.
During normal operation, the water pressure outside of containment is maintained 1
at 80 psig. Any significant leakage through this valve into containment would be j
detected as it would lead to the spray down of containment.
In a sense this i
valve is unde, continuous test (maintenance of the fire water system pressure
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boundary). The staff has concluded that this system configuration with the reverse direction Type C test with water provides adquate assurance that this valve is leak tight. Additionally, the licensee has proposed to flange the fire 3
water system outside of containment to allow venting of the fire water penetration j
during the ILRT. This will provide further assurance that this valve is leak
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tight. While the ILRT is not an individual test it assures that the total leakage through containment is below 0.75 La. Therefore, thc ILRT does provide reasonable assurance that the leakage through any one penetration is limited to at most 0.75 La. Therefore, the staff concludes that a permanent exemption for j
penetration P-80 to perform reverse direction testing with water satisfies the underlying purpose of the rule as the proposed testing and the system configura-tion provides adequate assurance that this penetration is leak tight.
3.0 EXEMPTIONS GRANTING TEMPORARY RELIEF j
The staff nas reviewed CYAPC0's submittal for exemptions granting temporary relief from Appendix J.
Some general comments on their requests are:
(1) The staff agrees that while the ILRT is not an individual test, it does provide overall assurance that containment atmospheric leakage from all sources is below a defined maximum. We note, however, that the basis for accepting this argument is predicated on the fact that I
during the ILRT the appropriate penetrations are vented and drained to be exposed to containment atmospheric pressure as in the post-accident case.
(2) The Region has informed the staff that CYAPC0 maintains the Haddam Neck containment at 1 to 2 psi at power. While this is obviously not equivalent to the ILRT, it does provide some indication of containment integrity.
(3) For those exemptions which are granted, the ultimate resolution will be determined as part of plant integrated assessment.
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-5 3.1 Exemption Requested Section II.H of 10 CFR Part 50, Appendix J requires that Type C tests be performed for containment isolation valves that:
1.
Provide a direct connection between the inside and outside atmospheres of the primary reactor containment under normal operation. such as purge and ventilation, vacuum relief, and instrument valves; 2.
Are required to close automatically upon receipt of a containment isolation signal in response to controls intended to effect containment isolation; j
3.
Are required to operate intermittent ~iy under post-accident conditions; and 4.
Are in main steam and feedwater piping and other systems which penetrate containment of direct-cycle boiling water power reactors.
CYAPC0 requests an exemption from the Type C testing requirements of Section II.H of Appendix J for the reactor coolant charging (P-8),
containment sump to residual heat removal (P-73), and high pressure safetyinjection(P-3) penetrations.
3.1.1 Licensee Basis for P-8 CYAPC0 had previously requested an exemption'from the Type C testing requirements of Appendix J for the reactor coolant charging (P-8) pene-j tration. This previous request was based on the seismic design of system piping inside containment and on the proposed seismic qualification of system piping from the isolation valves of Penetration P-8 to its water source.
Subsequent evaluations determined such qualification to be a lengthy and costly effort.
In the interim, although Penetration P-8 is currently not Type C tested, the isolation valves in this penetration are exposed to containment pressure through the vented reactor coolant system during the ILRT.
The valves are exposed to containment pressure in the direction of accident pressure with the backside of the valves depressurized.
- Further, the portion of the system outside containment is checked for liquid i
leakage in accordance with administrative Technical Specification 3.14.
System leakage is accounted for in offsite dose consequence calculations per 10 CFR Part 100. Such leak testing prcvides additional assurance that the potential for significant containment atmosphere leakage through this penetration is minimal.
CYAPC0 believes an exeniption from tne Type C testing requirements of Appendix J is justified based on the above information, as well as on j
the long lead time needed for equipment to modify this penetration, the level of design and analysis required, and the need to integrate these modifications with the-ultimate resolution of the SEP review of containment isolation valve configurations per 10 CFR 50, Appendix A.
This approach is consistent with the ALARA philosophy in that it avoids repetitive modifications to the same penetration. CYAPC0 proposes to resolve this issue within the framework of the ISAP.
Evaluation The charging system is seismic inside of containment and seismic outside of containment at least to the charging pumps. This is basically a closed system outside of containment. This system could be used during or after
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an accident and will be at least partially solid.
1 Conclusion The staff has concluded that, in the interim, the Type A test, in conjunction with the technical specification leakage limits for this system, provide reasonable assurance that leakage through.this penetration is limited. Additionally, the operation and physical configuration of the charging system will provide a good deterrent to any containment leakage past the isolation valves. Based on the above, the staff has concluded that this schedular exemption is warranted and that the granting of this exemption will not present undue risk to public health and safety.
3.1.2 Licensee Basis for P-73 ThecontainmentsumptoRHRsuctionline(P-73)penetrationhasnotbeen I
previously Type C tested.
It is isolated by three normally closed valves (RH-M0V-22, RH-V-808A and CC-CV-802). The motor operated valve RH-MOV-22 and manual valve RH-V-808A are located outside containment and isolate the RHR system that is operating during the ILRT; the backside of these valves is, therefore, not ventable during the ILRT. Appendix J does not require that these valves be tested since the RHR system will be filled with water and operating in the post-accident condition, considering a single-active failure. The RHR system, however, has an administrative technical specification leakage limit of 3 liters / hour (Reference LC0 3.14).
This leakage. limit encompasses the makeup, seal injection / return, and fill portions of the charging system as well. Any leakaSe through these systems is accounted for in offsite dose consequence calculations per 10 CFR Part 100.
i The third isolation valve of Penetration P-73 is a check valve CC-CV-802, which has not been previously local leak-rate tested. This valve isolates i
the components cooling water surge tank relief line. Should this valve fail to isolate, relief valve CC-RV-777 would prevent leakage. There-are effectively two leakage barriers in'this portion of the piping. _ The pcssi-i bility of an unisolated leak of containment atmosphere is, therefore, not 1
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credible. During a postulated accident, safety injection will fill the lower elevation of the containment and the containment sump with water for the duration of the long-tenn cooling phase. Therefore, a 30-day water seal exists for this portion of the penetration.
This penetration will be water tested in the future once physical modifi-cations have been completed to permit such testing. CYAPC0 believes an exemption from the Type C testing requirements of Appendix J is justified for valve CC-CV-802 based on the above information as well as the long lead time for equipment needed to modify this penetration, the level of design and analysis required, and the need to integrate these modifications with the ultimate resolution of the SEP review of containment isolation valve configurations per 10 CFR Part 50, Appendix A.
This approach is consistent with the ALARA philosophy in that it avoids repetitive modifications to the same penetration. CYAPC0 proposes to resolve this issue within the framework j
of the ISAP.
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Evaluation The containment sump to the RHR suction line is a safety grade, Class 2, I
scismic line.
The Type C water test, in this case, would be to confirm j
that a 30-day water seal can be maintained, the containment sump is filled I
during the long term cooling phase and there is no question that this line would be water filled for at least 30 days.
Conclusion l
The staff's opinion is that a 30-day water seal will exist in the j
containment sump. The staff does not require these valves to be Type C l
water tested, l
3.1.3 Licensee Basis for Penetration P-3 i
Valve SI-V-860 is a 3" locked close manual gate valve that isolates the cavity fill line. The cavity fill line branches off the high pressure safety injection header inside containment. This valve is not local leak rate tested, but is tested during the ILRT in the accident direction with air on the containment side of the valve. The downstream side of the valve is covered with liquid, but is vented during the ILRT.
This is consistent with the expected post-LOCA conditions because valve SI-V-860 is in a vertical run with liquid trapped above it due to testing of the high pressure safety injection system.
The recent PRA analysis of this penetration resulted in a total risk (due to non-compliance with Appendix J) of 0.9 man-rem over the life of the plant. Of the total risk, 0.3 man-rem is due to valve SI-V-860 not being tested.
It is assumed that SI-V-860 leaks 5% of the containment air volume per day, which is greater than twice the worst measured containment isolation valve as-found leakage at the plant.
Clearly, the risk due to this untested valve is very small. Since the ILRT does leak test this valve, the actual risk will be much less than 0.3 man-rem.
CYAPC0 believes an exemption from the Type C testing' requirements of Appendix J is justified based on the above information, as well as on the long lead time needed for equipment to modify this penetration; the level of design and analysis required; and the need to integrate these modifica-tions with the ultimate resolution of the SEP review of containment isolation valve configurations per 10 CFR Part 50, Appendix A.
This I
approach is consistent with the ALARA philosophy in that it avoids repetitive modifications to the same penetration. The ultimate resolution of this issue will be accomplished within the frame-work of the Haddam. Neck Plant ISAP.
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Evaluation a
f The high pressure safety injection (HPSI) system is a seismic, Class 1, I
safety grade system.
Penetration 3 has several branches. The cavity fill branch line is the only branch line of the HPSI that is not Type C tested.
This system is a closed system outside of containment and water solid to the pumps. The valve is exposed to containment atmosphere during the ILRT.
l Conclusion The staff has concluded that the Type A test will provide reasonable assurance that leakage through this valve is limited. Additionally, the operation and physical configuration of the HPSI system will provide a good deterrent to any containment leakage past this isolation valve.
Based on the above, the staff has concluded that this exemption is warranted and that the granting of this exemption will not present undue risk to public health and safety.
1 3.2 Exemption Reauested for Reverse Direction Testing Section III.C.1 of Appendix J to 10 CFR Part 50 states:
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" Type C tests shall be performed by local pressurization. The pressure shall be applied in the same direction as that when l
the valve would be required to perform its safety function, l
unless it can be determined that the results from the tests i
for a pressure applied in a different direction will provide equivalent or more conservative results...."
l CYAPC0 requests an exemption from the above requirement so that certain i
valves in the following penetrations may be tested in the reverse direction:
P-7 RCP Seal Water Return P-33 refueling cavity purification, and P-78 pressurizer relief tank drain.
An exemption is requested to allow the reverse direction testing of valve PU-V-242 in Penetration P-33, DH-TV-554 in Penetration P-78, and CH-RV-332.
in Penetration 7.
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'- l Licensee's Basis The refueling cavity purification (P-33) penetration is isolated by.two containment isolation valves. Valve PU-V-242A is Type C tested in the direction of accident pressure; valve PU-V-242 is tested in the reverse i
direction. The pressurizer relief tank drain (P-78) penetration is isolated by valves DT-TV-1844 and DH-TV-554. Valve DT-TV-1844 is tested in the direction of accident pressure; valve DH-TV-554 is tested in the reverse direction. CYAPC0 requests a temporary exemption to permit continued reverse direction testing of valves PU-V-242 and DH-TV-554 until modifications can be made to permit testing in the direction of accident pressure. Valves PU-V-242 and DH-TV-554 are tested at the proper direction during the ILRT. As previously concluded by the NRC Staff, a'ithough the ILRT is not performed as frequently as Type C leak rate tests, the ILRT does provide an indication of overall containment leak tightness, including penetrations.
1 Valve CH-RV-332 in Penetration P-7 has a seating force 3.5 times greater.
j than the force due to containment accident pressure of 40 psig. This j
ensures that the leak geometry is dominated by the seating force instead of the test direction. This valve is also bench tested once every five
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years for set pressure and leakage per Procedure PM 9.5-114.
It was so 1
tested during the 1986 outage in the accident direction and found to have no leakage.
CYAPC0 believes an exemption to permit reverse direction testing of valves DH-TV-554, PU-V-242, and CH-RV-332 is justified based on the above information, as well as by the level of design and analysis required to accomplish modifications to Penetrations P-33, P-78, and P-7 to permit testing in the direction'of accident pressure.
I Evaluation
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PU-V-242 is a 3" manual diaphragm valve, DH-TV-554 is a 2" gate valve and CH-RV-332 is a relief valve.
For valves DH-TV-554 and CH-RV-332 the seating force is 5.2 times and 3.5 times the calculated peak containment pressure force, respectively. As a general guideline, the NRC considers reverse testing conservative ~1f the seating force is ten times the calcu-lated peak pressure force. While this ensures that the leak geometry is dominated by the seating force instead of the test direction, there is no rigorous calculation for determining what other seating force may be acceptable.
In the interim, the staff believes that with the above seating forces these tests will provide reasonable leak rate data. Also,Section XI of the ASME Code requires that the set pressure and leakage for CH-RV-332 be confirmed once every five 3 ears.
For valve PU-V-242, CYAPCO states the design of the valve is such that leakage through the seat should be equal in either direction. The problem with this valve is the leakage through the bonnet may not be the same when tested in opposite
- directions.
The staff would not expect a large variation in leakage through the bonnet as this is a fixed seal.
In the interim, the staff believes the reverse test will provide reasonable leak rate data.
Additionally, these valves are tested in the accident direction during the ILRT with these valves exposed to containment atmosphere.
Conclusion Based on the above, the staff concludes that this exemption is warranted and that the granting of this exemption will not present undue risk to public health and safety.
3.3 Exemption Requested for Water Testing Section III.C.2.(a) of Appendix J to 10 CFR 50 states:
" Valves, unless pressurized with fluid (e.g., water, nitrogen) from a seal system, shall be pressurized with air or nitrogen at a pressure of P *"
a An exemption is requested from the requirement to test the following penetrations with air or nitrogen:
P-3 high pressure safety injection P-7 RCP seal water return P-10 RCS letdown P-11 RCS sampling P-24 safety injection recirculation P-28 CCW to RCP oil coolers P-30 space heating steam supply P-34 CCW from RCP thermal barrier P-38 CCW to RCP thermal barrier P-60 CCW to neutron shield cooler
'P-61 CCW from neutron shield cooler P-63 neutron shield fill P-66 CCW to drain cooler P-67 CCW from drain cooler P-68 primary water to containment P-69 loop fill P-74 RCP seal water supply P-75 RCP seal water supply P-76 RCP seal water supply P-77 RCP seal water supply l
Licensee Basis All of the penetrations listed above are tested with water during Type C testing. While no quantitative correlation between water and air leakages has been accepted by the NRC Staff to date, CYAPC0 believes that the current testing methods at the Haddam Neck Plant provide a means to l
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11 accurately identify those penetrations that represent significant leakage paths.
In all cases, plant procedures require repair and retesting of penetrations where specific individual valve liquid leakage limits are exceeded.
While a thirty-day water seal cannot be proven for tnese penetrations if only engineered safeguards equipment must be relied upon, these lines are normally water-filled and are likely to remain water-filled during the early stages of a postulated LOCA, when containment pressure peaks.
Approximately ten hours after the onset of a postulated accident, the containment pressure is less than 1.5 psig.
Hence, during the post-accident period when air leakage is most likely to occur, the driving force behind such leakage is substantially reduced.
Offsite dose calculations for the Haddam Neck Plant demonstrate that half of the site boundary thyroid dose due to containment leakage occurs during the first fifteen minutes following the onset of a postulated accident.
Temporary water seals in these penetrations are likely during the period when the dose consequences of a postulated accident are greatest.
In previous submittals to the NRC, CYAPC0 addressed elements of the scope of the Integrated Safety Assessment Program (ISAP) for the Haddam Neck Plant.
In these letters, CYAPC0 communicated to the NRC its position that, based upon the favorable experience of the Systematic Evaluation Program for the Haddam Neck Plant, a similar integrated evaluation 0; all pending regulatory requirements would result in the greatest increase in plant safety.
CYAPC0 identified the need for an integrated evaluation of modifications necessary to resolve 10 CFR Part 50, Appendix J, leak testing issues, and 10 CFR Part 50, Appendix A, containment isolation issues.
The NRC concluded that deferral of modifications to permit testing of certain penetrations with air or nitrogen was acceptable based on CYAPCO's address of this issue as part of the Haddam Neck Plant ISAP. As outlined in the July 31, 1985 letter to CYAPCO, the NRC has designated this issue as ISAP Topic 1.03, " Containment Penetrations."
Based on the above information, CYAPC0 believes an exemption from the requirements of Appendix J to permit water testing of the penetrations identified above is justified. The ultimate resolution of this issue will be accomplished with the framework of the Haddam Neck Plant ISAP. Additional penetration-specific justification for this exemption is provided below.
l 3.3.1 Penetrations P-7, P-69, P-74, P-75, P-76, and P-77 I
Leakage for these penetrations, which are the seal water return, loop fill, and seal injection portions of the charging system, is addressed by administrative Technical Specification 3.14.
The specification requires that these systems outside containment be checked for liquid leakage from seals, flanges, and valves. The leakage limit of 3 liters / hour, estab-lished by administrative Technical Specification 3.14 for these systems,
includes leakage from the RHR and charging makeup lines as well, and is included in the offsite dose consequence calculations per 10 CFR Part 100.
This provision for additional leakage limits provides further assurance that the potential for significant leakage of containment atmosphere through these penetrations is minimized.
l 3.3.2 Penetration P-10 While not safety-related, the letdown system is closed outside containment.
3.3.3 Penetration P-11 The RCS sampling lines consist, in part, of four small, i.e. 3/8" masoneilan globe valves, in parallel, which are normally isolated against full RCS pressure. Since these containment isolation valves tend to unseat more as pressure increases, testing at 2000 psig is, in fact, conservatively maximizing leakage through these valves.
3.3.4 Penetration P-28, P-34. P-38, P-60, P-61, P-63, P-66, and P-67 While not safety-related, the component cooling water system is closed inside containment and maintained at a normal pressure, in excess of accident pressure. With the exception of the component cooling surge tank vent, the system is also closed outside containment. The surge tank vent automatically isolates on high radioactivity in the vent line.
3.3.5 Penetration P-30 Leakage through this penetration would be filtered through the primary auxiliary building charcoal filters that tend to significantly reduce the iodine contribution to offsite doses.
3.3.6 Penetration P-68 Although the primary water system is not safety-related, it is closed inside containment and includes two check valves in series near the penetration. System pressure is normally maintained at a pressure greater than accident pressure.
3.3.7 Penetrations P-3 and P-24 The safety grade safety injection system operates at a pressure greater than the accident pressure Pa during the early stages of a design basis accident when containment pressure peaks. Therefore, the potential for containment atmosphere leakage only exists during a long-term post-LOCA period.
Evaluation The staff agrees that the Type C test performed with water will provide a reasonable indication that a valve is seated and reasonably leak tight.
Additionally, the Type A test with the above penetrations vented will
provide overall assurance that the containment leakage from all sources is below a defined maximum. The staff also agrees that the penetrations in this exemption will probably be water-filled early in the accident.
Appendix J requires that a thirty day water seal be confirmed before allow-
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ing water testing. CYAPC0 presently uses an air to water conversion factor that has not been accepted by the staff. CYAPC0 is performing research to establish an air to water conversion factor for NRC approval.
In the in-l terim, their use of a conversion factor does at least provide some quanti-fiable air leakage for each penetration.
l The CCW system has been a major source of leakage. CYAPC0 believes this has been due to a cross-tie line test between CCW and service water which introduces a slug of silt into the CCW every refueling outage. CYAPC0 states the cross-tie line tends to collect silt from the service water system when rot in use.
During the 1984 refueling outage, a filtration system was added to the CCW and in 1986 its capacity was increased.
CYAPC0 agreed to an increased local leak rate test (LLRT) for the CCW penetrations to check the effectiveness of this modification. During a July 1986 shutdown, CYAPC0 retested five penetrations in the CCW and found them to be within technical specification leakage limits. CYAPC0 has also proposed to install a flushing tee in the cross-over line during the 1987 outage. CYAPC0 believes these actions will resolve the silt problem with the CCW system.
In addition to the above modifications, CYAPC0 has proposed to modify the following penetrations:
1)
P-7 Reactor Coolant Seal Water Return 2)
P-10 Reactor Coolant System Letdown 3)
P-30 Space Heating Supply 4)
P-38 CCW to RCP Thermal Barrier 5)
P-60 CCW to Neutron Shield Tank Cooler 6)
P-23B Obsolete Systems through D 7) P-31, 35, Spare Penetrations 36, 37, 59, and 72B The decision to modify these penetrations was based on the results of l
a risk analysis (ISAP Topic 1.03) and a review of Haddam Neck's Type A 1
and C test results over the last three outages.
Based on the LLRT, CYAPC0 concluded that P-38 and P-60 in the CCW system i
are more susceptible to silt build-up on the valve seats because of valve type and physical orientation.
CYAPC0 proposed to modify the penetrations, replacing the existing valves with air-operated valves (A0V) that can be air tested in the accident direction.
CYAPC0 also proposes to modify P-68.
This valve has a poor leakage history, which CYAPC0 believes is'due to valve type and the steam environment. CYAPC0 proposes to install a bypass line with the appropriate isolation valves to
_ 14 alleviate this problem. Based on their risk analysis, C(APC0 proposes to modify P-7 and P-10, which are the two highest ranked risk contributors for this exemption request. Both these penetrations are in the chemical volume and control system.
With these modifications CYAPC0 will comply with Appendix J for 5 of the 15 penetrations in this exemption request.
Additionally, 8 of the 15 6 penetrations are in the CCW system which will be modified to eliminate the silt problem. These actions were taken independent of ISAP. The staff concludes that CYAPC0, with these modifications, has taken prudent steps in improving Haddam Neck's containment integrity from both a risk and operating experience perspective. The modifications and improvements
' demonstrate CYAPCO's good faith efforts in seeking resolution of the Appendix J issue.
Individual penetration exemption requests are discussed below in the following four groups:
1)
High Pressure Injection, 2)
Letdown and Charging, 3)
Component Cooling Water, and 4)
Space Heating and Primary Water.
High Pressure Safety Injection (P-3,P-24)
The high pressure safety injection (HPSI) system is a seismic, Class 1,-
safety grade system. Penetration 24 is the HPSI pump test recirculation lines. These lines are 3/4" with normally lock-closed valves.
Penetration 3 is the HPSI injection line. This system is a closed system outside of containment and water solid to the pumps. This system is not vented during the ILRT.
This system will be used to inject water into the RCS early in the ac::ident when peak pressure occurs.
Leakage is only a concern later in the accident when the pumps are turned off. At the later stages of an accident, leakage would be limited because it is a safety grade, seismic, closed system outside of containment that is partially solid.
- Further, containment pressure should be substantially lower at this time.
Conclusion l
The staff has concluded that the Type C test with water, and using a water to air coversion will provide, in the interim, reasonable assurance that these valves are leak tight.
Additionally, the operation and physical configuration of the HPSI system will be a good deterrent to any containment leakage past the isolation valves. Based on the above, the staff has concluded that this exemption is warranted and that the granting of this exemption will not present undue risk to public health or safety.
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1 Letdown and Charging (P-7, P-10, P-11, P-69, and P-74 through P-77)
The letdown and charging system is basically a seismic, Class 1 system inside of containment and Class 2 outside.
CYAPC0 considers this system to be a closed system outside of containment, but cannot assure the system is totally seismic outside. This system probably would remain water-filled during the early stages of a postulated LOCA. Later in the accident, leakage would be limited because it is a closed system outside of containment that is partially solid. Additionally, CYAPC0 has established Technical Specification 3.14 to assure that liquid leakage is limited during normal operation. The combined leakages from CVCS and RHR must be less than 3 liters per hour.
CYAPC0 has proposed to modify P-7-and P-10 during the 1987 refueling
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I outage. These modifications will provide two valves and allow Type C air testing. CYAPC0 has also informed the staff that the piping associated i
with P-69 is seismic inside of containment and seismic from the penetration to the charging pumps outside.
P-11 is the RCS sampling line. These lines are 3/8" diameter and are normally isolated against full RCS pressure (2000 psig) with rasoneilan globe valves. This type valve tends to unseat at higher pressures.
The maintenance of the RCS pressure boundary at 2000 psig is a good indication of the laak tightness of these valves.
P-74 through P-77 are the reactor coolant pump seal injection lines.
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This is basically a Class 2, non-seismic, closed system inside and outside of containment.
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Conclusion l
l The staff has concluded that the Type C test with water, and using a water to air conversion will provide, in the interim, reasonable assurance that these valves are leak tight. Additionally, the operation and physical configuration of the CVCS will be a good deterrent to any containment leakage past the isolation valves. Based on the above, the staff has concluded that this exemption is warranted and that the granting of this exemption will not present undue risk to public health and safety.
Component Cooling Water (P-28,P-34,P-38,P-60,P-61,P-63,P-66, and P-67)
The component cooling water system is a Class 3, closed loop system inside and outside of containment.
It is missile protected inside of containment. While the system is not seismic, it would require a rupture of the piping before the isolation valves would be exposed to containment atmosphere.
This system has contained the worst leakers in the Type C test for the last i
several outages.
In an effort to alleviate this problem, CYAPC0 has added a filtration system and proposed several modifications, as discussed earlier, i
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Conclusion The staff has concluded that the Type C test with water and using a water to air conversion will provide, in the interim, reasonable assurance that these valves are leak-tight. Additionally, the addition of a filtration system and proposed modifications for the 1987 refueling outage for the CCW will improve the leak worthiness of the penetrations in this system. Based on the above, the staff has concluded that this exemption is warranted and the granting of this exemption will not present undue risk to public health and safety.
Steam Space Heating Supply and Primary Water to Containment (P-30 and P-68)
These are non-safety related, closed systems inside of containment.
Each penetration has two check valves in series.
Even though these systems are not safety-related, it would require a rupture of the pipe before the isolation valves would be exposed to containment atmosphere.
As discussed earlier, because of the poor leakage history of P-30, CYAPC0 has proposed to modify this penetration.
Conclusion The staff has concluded that the Type C test with water, and using a water to air conversion will provide, in the interim, reasonable assurance that these valves are leak tight. Additionally, CYAPC0 has agreed to modify P-30, to conform with the requirements of Appendix J.
Based on the above, the staff has concluded that this schedular exemption is warranted and tt.at the granting of this exemption will not present undue risk to public health and safety.
3.4 Exemption Requested for Testing at Pressures Greater Than Pa.
Section III.C.2 of Appendix J to 10 CFR Part 50 states:
(a) Valves, unless pressurized with fleid (e.g., water, nitrogen) from a seal system, shall be pressurized with air or nitrogen at a pressure of Pe.
(b) Valves, which are sealed with fluid from a seal system, shall be pressurized with that fluid to a pressure not less than 1.10 Pa.
An exemption is requested for the following penetrations to allow testing these valves at pressures greater than Pa.
P-11 RCS Sampling P-63 neutron shield fill P-69 loop fill
'* Licensee Basis In a preceding section of this evaluation it was noted that CYAPC0 had requested an exemption from the requirements of Appendix J to permit continued Type C testing of the above penetrations with water rather than air.
Currently, these water-filled, water-tested penetrations are tested at pressures that are roughly equivalent to the normal system pressure. The test pressures are listed below.
P-11:
2000 psig P-63:
70 psig P-69:
2000 psig In previous submittals, CYAPC0 discussed plans to modify these penetrations to permit Type C testing at accident pressure Pa.
CYAPC0 believes that the requested exemption is justified based on the information provided below, as well as the long lead time needed for equipment to modify these penetrations, the level of design and analysis required, and the need to integrate these modifications with the ultimate resolution of the SEP review of containment isolation valve configurations per 10 CFR Part 50, Appendix A.
The ultimate resolution of this issue will be accomplished within the framework of the Haddam Neck Plant ISAP. Additional penetration specific justification is provided below.
3.4.1 Penetration P-11 This penetration is tested at reactor coolant system pressure rather than Pa.
The RCS sampling lines consist, in part, of four small, i.e., 3/8" masoneilan globe valves, in parallel. These containment isolation valves would tend to be unseated more as pressure increases. Therefore, these valves would leak more when tested at RCS pressure (2000 psig) than when tested at accident pressure (40 psig). CYAPC0 believes that the current test pressure of 2000 psig conservatively maximizes leakage through these valves.
3.4.2 Penetration P-63 As previously discussed, valve CC-V-884 in Penetration P-63 is a manual, Grinnell weir-type diaphragm valve that has symmetric internals and a single seating surface. The valve is currently tested in the reverse direction and would tend to unseat equally with pressure applied in either direction.
Through-valve leakage due to a test pressure greater than accident pressure, i.e., at CCW system pressure, will be conservatively larger than through-valve leakage at accident pressure Pa.
Nevertheless, Haddam Neck Plant procedures have been revised to conserva-tively maximize the total penetration leakage to include any leakage from the containment side of the penetration. To accomplish this, leakage will be collected from the valve stem and body-to-bonnet flange with the valve in the open position and the system pressurized. Leakage measured in this fashion will be added to measured through valve leakage. This process will
'. conservatively maximize the total leakage to include any leakage on the containment side of the diaphragm.
It is, therefore, appropriate to test this penetration at a pressure greater than Pa.
3.4.3 Penetration P-69 This penetration is tested at RCS pressure. Any post-accident leakage would be filtered by the PAB charcoal filters. As previously discussed, administrative Technical Specification 3.14 requires that the combined leakages of the seal water return (P-7), loop fill (P-69), and seal injection charging (P-74, 75, 76, and 77) systems outside containment be liinited to 3 liters / hours. This leakage limit is also shared with the RHR and charging makeup lines and is included in the 10 CFR Part 100 dose calculations. This provision for additional leakage limits provides further assurance that the leakage of containment
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post-accident atmosphere through Penetration P-69 is minimized.
Evaluation P-11 P-11 is the RCS sampling line. This penetration was discussed in the previous exemption request. The design of this valve is such that the test pressure of 2000 psig would tend to unseat the valve and increase leakage.
In a sense, the i
sampling vr.lves are in continuous test. These lines are in a monitored area and any leakage during operation would be detected immediately.
Conclusion Based on the above, the staff believes this exemption is warranted and that the granting of this exemption will not present undue risk to public healtn and safety.
P-63 l
P-63 is the neutron shield fill line. This penetration was discussed in the previous exemption request.
The design of this valve is such that the test i
pressure of 70 psig would tend to unseat _the valve and increase leakage.
I Conclusion Based on the above, the staff believes this exemption is warranted and that the granting of this exemption will not present undue risk to public health and safety.
P-69 1
P-69 is the loop fill line. This penetration was discussed in our previous evaluation for Type C testing with water. This is a Class 1, seismic line inside of containment and normally isolated from the RCS. The isolation valve is a check valve, which would tend to be seated tighter at the test pressure of 2000 psig. As stated earlier, this line is vented during the ILRT.
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. Conclusion The ILRT and the LLRT at high pressure and with water provide reasonable assurance that this valve is leak tight. Additionally, the operation of the charging system and the physical configuration of this line will be a good deterrent to any containment leakage.
Based on the above, the staff has concluded that this schedular exemption is warranted and that the granting of of this exemption will not present undue risk to public health and safety.
4.0 ACKNOWLEDGEMENTS This Safety Evaluation was prepared by A. Wang, ISAPD, DRSP with assistance from J. Pulsipher, SPLB, NRR.
Dated: September 29, 1987 4
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