ML17258B080
| ML17258B080 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 05/26/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17258B078 | List: |
| References | |
| NUDOCS 8106050052 | |
| Download: ML17258B080 (11) | |
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UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION INSERVICE TESTING PROGRAM - VALVES ROCHESTER GAS AND ELECTRIC CORPORATION R.
E.
GINNA NUCLEAR POWER PLANT PROVISIONAL OPERATING LICENSE DPR-18 DOCKET NO. 50-244 1.0 VALVE TESTING PROGRAM
- 1. 1 General Considerations 1.1.1 Testin of Valves Which Perform a Pressure Isolation Function Several safety systems connected to the reactor coolant pressure boundary have design pressures below the reactor coolant system operating pressure.
Redundant isolation valves within the Class 1 boundary forming the interface between these high and low pressure systems prevent the low pressure systems from pressures which exceed their design limit.
In this role, the valves perform a pressure isolation function.
We view as important the redundant isolation provided by these valves.
We consider it necessary to assure that the condition of each of these valves is adequate to maintain this redundant isolation and system integrity.
For these
- reasons, we believe that some method, such as pressure monitoring, leak test-ing, radiography and ultrasonic testing should be used to assure the condition of each valve is satisfactory in maintaining this pressure isolation function.
If leak testing is selected as the appropriate method for achieving this objective, the staff believes that the following valves should be categorized as A or AC and leak tested according to IWV-3420 of Section XI of the applicable edition of the ASME Code.
These valves are:
853A (Coi e Deluge Check) 853B (Core Deluge Check) 878J (1-B SI Pump to Cold Leg Loop A) 878G (1-A SI Pump to Cold Leg Loop B) 852A (RHR Pump to RX Vessel) 852B (RHR Pump to RX Vessel)'42A (First Check Valve in Loop A ACC Dump Line) 842B (First Check Valve in Loop B
ACC Dump Line) 867A (ACC Dump and SI to Cold Leg Loop B) 867B (ACC Dump and SI to Cold Leg Loop A)
700 (Suction Stop from Loop A Hot Leg to RHR Pumps) 701 (Suction Stop from Loop A Hot Leg to RHR Pumps) 720 (RHR Pump Discharge to Cold Leg Loop B) 721 (RHR Pump Discharge to Cold Leg Loop B) 877A (First Check Valve in Loop B Hot Leg) 878F (Second Check Valve in Loop B Hot Leg) 877B (First Check Valve in Loop A Hot Leg) 878H (Second Check Valve in Loop A Hot Leg)
We have discussed this matter with the licensee and identified the valves listed above.
The licensee agreed to consider testing and categorizing each of these valves with the appropriate designation depending on the testing method selected.
Whatever method the licensee selects for determining the condition of each valve, the licensee wi 11 provide to the NRC for evaluation the details of the testing method which clearly demonstrate the con'dition of each valve.
The licensee should be aware that some of the above listed valves may be associated with the Event V configuration issue expressed in our letter to the licensee dated February 23, 1980.
If the licensee action as a result of this and other followup NRC letters on this subject matter is to test the valves, then the licensee should identify the valves and provide us the testing method and procedure if they have not already done this.
The February 23, 1980 letter was the initiation on our part to accelerate our effort to begin having licensees testing pressure isolation valves.. It is the staff position that all pressure isolation valves identified in this section must be considered for testing.
- 1. 1. 2 Stroke Testin Check Valves
'he staff 'stated its position to the licensee that check valves whose safety function is to open are expected to be full-stroked.
If only limited opera-tion is possible (and it has been demonstrated by the licensee and agreed to by the staff) the check valve shall be partial stroked.
Since disk position is not always observable, the NRC staff stated that verification of the plant's safety analysis flow rate through the check valve would be an adequate demon-stration of the full-stroke requirement.
Any flow rate less than design will be considered part-stroke exercising unless it can be shown that the check valve's disk position at the lower flow rate would be equivalent to or greater than the design flow rate through the valve.
The licensee agreed'to accept this position if they use flow as a means of exercising check valves.
- 1. 1.3 Stroke Testin of Motor-0 crated Valves The licensee has requested relief from the part-stroke requirement of Section XI for all power-operated valves.
The licensee has stated that none of the Category A or B power-operated
'valves addressed in this -SER'can be part-stroked because of the design logic of the operating circuits.
These circuits are such that when an open or close signal is received the valve must complete a full stroke before the relay is released to allow the valve to stroke in the..'ther direction.
We find that the above relief request from part-stroking is warranted because it is impractical to part-stroke and should be granted because the required function of the valves involves only full-open or full-closed positions.
Therefore, we conclude that granting this relief does not endanger public health and safety.
l 7
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- 1. 1.4 Test Fre uenc of Check Valves Tested at Cold Shutdowns The Code states that, in the case of frequent cold shutdowns, valve.testing need not be performed mor e often than once every three months for Category A
and 8 valves and once every nine months for Category C valves (check valves only). It is our position that Category C valves should be tested on the same schedule as Category A and B valves.
This position is also in agree-ment with the current edition and addenda of the Code.
The licensee has agreed to this position that valve testing will not be performed more often than once every three (3) months for Category A, B, and C valves.
- 1. 1.5 Licensee Re uest for Relief to Test Valves at Cold Shutdown The Code permits valves to be tested at cold shutdown, and the Code conditions under which this is permitted are noted in Attachment A.
These valves are speci-fically identified by the licensee and are full-stroke exercised during cold shutdowns; therefore, the licensee is meeting the requirements of the ASHE Code and it will not be necessary to grant relief.
However, during our review of the licensee's IST program, we have verified that it was not prac-tical to exercise these valves during power operation and that we agree with the licensee's basis.
It should be noted that the staff differentiates for valve testing purposes between the cold shutdown mode and the refueling mode.
That is, for testing purposes the refueling mode is not considered as a cold shutdown.
- 1. 1.6 Chan es to the Technical S ecification In a November 1976 letter to the licensee, we provided an attachment entitled "NRC Guidelines for Excluding Exercising (Cycling) Tests of Certain Valves During Plant Operation."
The attachment stated that when one train of a redundant system such as in the Emergency Core Cooling System (ECCS)is inop-
- erable, nonredundant valves in the remaining train should not be cycled if their failure in a non-safe position would cause a loss of total system function.
For example, during power operation in some plants, there are stated minimum requirements for systems which allow certain limiting condi-tions for operation to exist at any one time and if the system is.not restored to meet the requirements within the time period specified in a plant's Technical Specifications (T.S.), the reactor is requir'ed to be put in some other mode.
Furthermore, prior to initiating reports, all valves and interlocks in
,the system that provide a duplicate function are required to be tested to demonstrate operability immediately and periodically thereafter during power operation.
For such plants this situation could be contrary to the NRC guide-line as stated in the document mentioned above.
It should be noted that reduction in redundancy is not a basis for a T.S.
change nor is it by itself a basis for relief from exercising in accordance with Section XI.
'The licensee has agreed to review the plant's T.S.
and to consider the need to propose T.S.
change which would have the effect of precluding such testing.
1
After making this review, if the licensee determines that the T.S.
should be changed because the guidelines are applicable, the licensee will submit to the NRC in conjunction with the proposed T.S.
- change, the inoperable condition for each system that is affected which demonstrates that the valve's failure would cause a loss of system function.
Conversely, if the licensee determines that the T.S.
should not be changed because the guidelines are not applicable or cannot be followed, the licensee will submit the reasons that led to their determination for each potentially affected section of the T.S.
I l.l. 7 Safet -Related Valves This review was limited to safety-related valves.
Safety-related valves are defined as those valves that are needed to mitigate the consequences of an accident and/or to shut down the reactor and to maintain the reactor in a cold shutdown condition.
Valves in this category would typically include certain ASME Code Class 1, 2, and 3 valves and could include some non-code Class valves.
It should be noted that the licensee may have included nonsafety-related valves in their Inservice Test Program as a decision on the licensee's part to expand the scope of their program.
- 1. 1.8 Valve Testin at Cold Shutdown Inservice valve testing at cold shutdown is acceptable when the following conditions are met: It is understood that the licensee is to commence testing within two hours after cold shutdown condition is achieved but not later than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after shutdown and continue until complete or plant is ready to return to power.
Completion of all valve testing is not a prerequisite to return to power.
Any testing not completed at one cold shutdown should be performed during any subsequent cold shutdowns that may occur before refueling to meet the Code-specified testing frequency.
For planned cold shutdowns, where the licensee will complete all the valves identified in his IST program for testing in the cold shutdown mode, exceptions to the 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> may be taken.
The licensee has agreed to consider testing in accordance with these requirements.
- 1. 1.9 Cate or A Valve Leak Check Re uirements for Containment Isolation Valves (CIV)
All CIVs shall be classified as Category A valves.
The Category A valve leak rate test requirements of IWV-3420(aw ) have been superseded by Appendix J requirements for CIVs.
The staff has concluded that the applicable leak t'est procedures and requirements for CIVs are determined by 10 CFR 50 Appendix J.
Relief from paragraph IWV-3420 (a-e) for CIVs presents no safety problem since the intent of IWV-3420 (a-e),
which is to demonstrate the leak tightness of the valves, is met by Appendix J requirements.
The licensee shall comply with Sections f and g of IWV-3420 until relief is requested from these paragraphs.
It should be noted that these paragraphs are only applicable where a Type C Appendix J leak test is performed.
2 Based on the considerations discussed
- above, the staff concludes that the alternate testing proposed above will give the reasonable assurance of valve operability intended by the Code and that the relief thus granted will not endanger life or property or the common defense and security of the public.
- 1. 1. 10 A
lication of A endix J Testin to the IST Pro ram The Appendix J review for this plant is a completely separate review from the IST program review.
However, the determinations made by that review are directly applicable to the IST program.
Our review has determined that the current IST program as submitted by the licensee correctly reflects our inter-pretation of Section XI vis-a-vis Appendix J.
The licensee has agreed that, should 'the Appendix J program be amended, they will amend their IST program accordingly.
1.2 Safet In ection S stem 1.2.1 ~2~22 1.2.1.1
~Rfi 2
R Exclude check valves 867A (Accumu'lator Dump and SI to Cold Leg Loop B) and 867B (Accumulator Dump and SI to Cold Leg A) from the quarterly full stroking ASME Section XI Code requirements.
Instead, full stroking of these valves will be done at cold shutdown condition, with a partially full primary system, and at refuelings.
Code Re uirement Refer to Attachment A.
i Licensee's Basis for Re uestin Relief These valves cannot be stroked during normal operation on a quarterly basis because this test cannot be done when the primary system is at operating pressure.
Evaluation These valves form the pressure boundary between the primary coolant system and the safety injection system.
Full and partial stroki'ng is impractical because there is no way to overcome reactor coolant pressure during power operation to establish flow in order to test these check valves.
During cold shutdown's, full and partial stroking is not feasible because it creates a potential overpressurization situation due to the difficulty in controlling the plant from going solid.
Testing will be done at cold shutdown condition only when there is a partially full primary system in order to prevent the plant from going solid.
This configuration is the exception rather than the rule.
Check valves are found to be low in failure rate.
"Low in failure rate" has been defined as any component whose unavailability upon demand is less than or equal to 10-4 per demand.
The optimum test interval far operability testing "low in failure rate" valves was determined by the staff, using actual valve failure rate data and standard probabilistic techniques, to be in the range of 3 months to 27 months.
Refueling intervals, which will be the likely test intervals for, these valves~
occur every 12 to 24 months which is within the optimum range for operability testing of these valves.
The ASHE Code, which requires testing be done quarterly and which has been adopted in 10 CFR 50.55a, also allows testing at cold shutdowns if quarterly testing is impractical.
Cold shutdowns can occur at intervals up to refueling outages.
Therefore, changing the test interval from quarterly to refueling does not differ significantly from the Code-permitted change from quarterly to cold shutdown testing.
Conclusion Based on the above, the staff concluded that the alternate testing frequencies proposed above will give the reasonable assurance of valve operability intended by the Code and that the relief thus granted will not endanger public health and safety.
1.2.1.2
~f1 i 2
R Exclude check valves 878G (1-A SI Pump to Cold Leg Loop B) and 878J (1-B SI Pump to Cold Leg Loop A) from the quarterly full-stroking requirements.
Instead full stroking of these valves will be done at cold shutdown condition with a partially full primary system and refuelings.
~22 II Refer to Attachment A.
Licensee's Basis for Re uestin Relief These valves cannot be stroked during normal operation on a quarterly basis because this test cannot be done when the primary system is at operating pressure.
This test may'nly be done when the plant is in a cold shutdown condition with a partially full primary system in order to prevent an over-pressurization event.
2 Evaluation Full stroking is impractical because there is no way to overcome reactor coolant pressure during power operation to establish flow in order to test these check valves.
During cold shutdowns full and partial stroking is not feasible because it creates a potential overpressurization situation due to the difficulty in controlling the plant from going solid.
Testing will be done at cold shutdown only when there is a partially full primary system in order to prevent the plant from going solid.
This configuration is the exception rather than the rule.
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Check valves are found to be low in failure rate.
"Low in failure rate" has been defined as any component whose unavailability upon demand is less than or equal to 10-~ per demand.
The optimum test interval for operability testing "low in failure rate" valves was determined by the staff, using actual valve failure rate data and standard probabilistic techniques, to be in the range of 3 months to 27 months.'efueling intervals, which will be the likely test interval for these
- valves, occur every 12 to 24 months, which is within the optimum range for operability testing of these valves.
The ASME Code, which requires testing be done quarterly and which has been adopted in 10 CFR 50.55a, also allows testing at cold shutdowns if quarterly testing is impractical.
Cold shutdowns can occur at intervals up to refueling outages.
Therefore, changing the test interval from quarterly to refueling does not differ significantly from the Code-permitted change from quarterly to cold shutdown testing.
Conclusion Based on the above, the staff concluded that the alternate testing frequencies proposed above will give the reasonable assurance of valve operability intended by the Code and that the relief thus granted will not endanger public health and safety.
1.3 Instrument Air S stem 1.3.1 Cate or A Valves 1..1.1
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R The licensee has requested to exercise the following valves at refuelings in lieu of Section XI requirements.
AOV-5392 Instrument Air to Containment Isolation CV-5393 Instrument Air to Containment Isolation Code Re uirement Refer to Attachment A.
Licensee's Basis for Re uestin Relief R
R
/
Stroking Valves 5392 an'd 5393 during operation and cold shutdown would interrupt instrument air to containment and be disruptive to air-operated valves inside containment.
Evaluation Loss of instrument air would cause all air-operated valves to be actuated,to their fail-safe position.
During power, this would lead to a reactor trip and during cold shutdowns, this would compromise plant operation due to the loss-of various components used in maintaining the reactor in a cold shutdown mode.
Based on the above, the staff has determined that the exercising requirements of Section XI are impractical for these valves.
These valves are redundant.
Redundant means the existence of more than one valve for performing a given function.
The optimum test interval for operability testing redundant valves was determined by the staff, using actual valve failure rate data and standard probabilistic techniques, to be in the range of 3 months to 27 months.
Refueling intervals, which have been proposed as the test intervals for these
- valves, occur every 12 to 24 months, which is within the optimum range for operability testing of these valves.
The ASME code, which requires testing be done quarterly and which has been adopted in 10 CFR 50. 55a, also allows t'esting at cold shutdowns if quarterly testing i's impractical.
Cold shutdowns can occur at intervals up to refueling outages.
Therefore, changing the test interval from quarterly to refueling does not differ significantly from the Code-permitted change from quarterly to cold shutdown testing.
Conclusion Based on the considerations discussed
- above, the staff concluded that the alternate testing frequencies proposed above will give the reasonable assurance of valve operability intended by the Code and that the relief thus granted will not endanger public health and safety.
The relief does not involve significant new safety information of a type not considered by a previous Commission safety review of the facility. It does not involve a significant increase in the probability or consequences of an accident, does not involve a significant decrease in a safety margin, and, therefore, does not involve a significant hazards consideration.
We have also concluded that there is reasonable assurance that the health and safety of the of the public will not be endangered by this action and that the issuance of this relief will not bo inimical to the common defense and security or to the health and safety of the public.
Date:
May 26, 1981
ATTACHMENT A Code Re uirements Subsection IWV-3410(a) of the 1974 Edition of the Section XI ASME Code (which discusses full stroke and partial stroke requirements) requires that Code Category A and B valves be exercised once every three months, with ~exce tions as defined in IWV-3410(b) (1), (e) and (f).
IWV-3520(l) (which discusses full stroke and partial stroke requirements) requires that Code Category C valves be exercised once every three months, with exce tions as defined in IWV-3520(b).
In the above cases of exceptions, the Code perm>ts the valves to be tested in cold shutdown where:
(a) It is not practical to exercise the valves to the position required to fulfilltheir function or to the partial position durin ower o eration.
(b) It is not practical to observe the operation of the valves (with failsafe actuators) upon loss of actuator power.
Subsection IWV-3410(c) requires all Category A and B power-operated valves to be stroke time tested to the nearest second or lOX of the maximum allowable owner-specified stroke time.