L-91-008, Technical Specification Bases Change
| ML020430038 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 01/07/2002 |
| From: | Mccollum W Duke Energy Corp |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-91-008 | |
| Download: ML020430038 (23) | |
Text
-
Duke ir Energy W R. McCollum, Jr.
Vice President Duke Energy Oconee Nuclear Station 7800 Rochester Highway Seneca, SC 29672 (864) 885-3107 OFFICE (864) 885-3564 FAX January 7, 2002 U.
S.
Nuclear Regulatory Commission Washington, D. C.
20555 Attention: Document Control Desk
Subject:
Oconee Nuclear Station Docket Numbers 50-269,
- 270, and 287 Technical Specification Bases (TSB)
Change Please see attached revisions to Technical Specification Bases (TSB) 3.6.3 -
Containment Isolation Valves, which were implemented on December 18, 2001.
The change revises the bases to include the following statement related to administrative controls: The opening of locked or sealed closed containment isolation valves on an intermittent basis under administrative control includes the following:
(1) stationing an operator, who is in constant communication with control room, at the valve controls, (2) instructing this operator to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment.
The following statement was taken directly from GL 91-08.
GL 91 08 was also added as reference #5 to the reference section of the TS Bases. contains the new TSB pages and Attachment 2 contains the markup version of the Bases page.
If any additional information is needed, please contact Larry E.
Nicholson, at (864-885-3292).
Very truly yours, W. R.
- McCollum, Oconee Nuclear Vice President AcuDý
U.
S.
Nuclear Regulatory Commission January 7, 2002 Page 2 cc:
Mr.
L.
N. Olshan Office of Nuclear Reactor Regulation U.
S.
Nuclear Regulatory Commission Washington, D.
C.
20555 Mr.
L.
A.
Reyes, Regional Administrator U.
S.
Nuclear Regulatory Commission -
Region II Atlanta Federal Center 61 Forsyth St.,
SW, Suite 23T85 Atlanta, Georgia 30303 M. C.
Shannon Senior Resident Inspector Oconee Nuclear Station Virgil R.
Autry, Director Division of Radioactive Waste Management Bureau of Land and Waste Management Department of Health & Environmental Control 2600 Bull Street
- Columbia, SC 29201
Containment Isolation Valves B 3.6.3 B 3.6 CONTAINMENT SYSTEMS B 3.6.3 Containment Isolation Valves BASES BACKGROUND The containment isolation valves form part of the containment pressure boundary and provide a means for fluid penetrations not serving accident consequence limiting systems to be provided with two isolation barriers that are closed on an automatic isolation signal. These isolation devices consist of either passive devices or active (automatic) devices. Manual valves, non-automatic power operated valves in their closed position, de-activated automatic valves secured in their closed position (including check valves with flow through the valve secured), blind flanges, and closed systems are considered passive devices. Check valves, or other automatic valves designed to close following an accident without operator action, are considered active devices. Two barriers in series are provided for each penetration so that no single credible failure or malfunction of an active component can result in a loss of isolation or leakage that exceeds limits assumed in the safety analyses. One of these barriers may be a closed system. These barriers (typically containment isolation valves) make up the Containment Isolation System.
Containment isolation occurs upon receipt of a high containment pressure or diverse containment isolation signal. The containment isolation signal closes automatic containment isolation valves in fluid penetrations not required for operation of engineered safeguard systems to prevent leakage of radioactive material. Upon actuation, automatic containment valves also isolate systems not required for containment or Reactor Coolant System (RCS) heat removal. Other penetrations are isolated by the use of valves in the closed position or blind flanges. As a result, the containment isolation valves (and blind flanges) help ensure that the containment atmosphere will be isolated in the event of a release of radioactive material to containment atmosphere from the RCS following an accident.
OPERABILITY of the containment isolation valves (and blind flanges) supports containment OPERABILITY during accident conditions.
The OPERABILITY requirements for containment isolation valves help ensure that containment is isolated within the time limits assumed in the safety analysis. Therefore, the OPERABILITY requirements provide assurance that the containment function assumed in the safety analysis will be maintained.
BASES REVISION DATED 12/18/01 I OCONEE UNITS 1, 2, & 3 B 3.6.3-1
Containment Isolation Valves B 3.6.3 BASES BACKGROUND (continued)
The Reactor Building Purge System is part of the Reactor Building Ventilation System. The Purge System was designed for intermittent operation, providing a means of removing airborne radioactivity caused by minor leakage from the RCS prior to personnel entry into containment. The Reactor Building Purge System consists of one 48 inch line for exhaust and one 48 inch line for supply, with exhaust fans capable of purging the containment atmosphere at a rate of approximately 35,000 ft /min. The reactor building purge supply and exhaust lines each contain two isolation valves that receive a reactor building isolation signal.
Failure of the purge valves to close following a design basis event would cause a significant increase in the radioactive release because of the large containment leakage path introduced by these 48 inch purge lines. Failure of the purge valves to close would result in leakage considerably in excess of the containment design leakage rate of 0.25% of containment air weight per day (La) (Ref. 1). Because of their large size, the 48 inch purge valves are not qualified for automatic closure from their open position under accident conditions. Therefore, the 48 inch purge valves are maintained sealed closed (SR 3.6.3.1) in MODES 1, 2, 3, and 4 to ensure the containment boundary is maintained.
APPLICABLE SAFETY ANALYSES The containment isolation valve LCO was derived from the assumptions related to minimizing the loss of reactor coolant inventory and establishing containment boundary during major accidents. As part of the containment boundary, containment isolation valve OPERABILITY supports leak tightness of the containment. Therefore, the safety analysis of any event requiring isolation of containment is applicable to this LCO.
The accident that results in a significant release of radioactive material within containment is a loss of coolant accident (LOCA)(Ref. 2). In the analysis for this accident, it is assumed that containment isolation valves are either closed or function to close within the required isolation time following event initiation. This ensures that potential paths to the environment through containment isolation valves (including reactor building purge valves) are minimized. The safety analysis assumes that the 48 inch purge valves are closed at event initiation.
The LOCA analysis assumes a fixed amount of core inventory escapes.
No mechanistic scenario is evaluated to determine what portion of the inventory is released prior to closure of the containment isolation valves.
Industry standards for sizing valve operators govern the closure times of the containment isolation valves.
BASES REVISION DATED 12/18/01 I OCONEE UNITS 1, 2, & 3 B 3.6.3-2
Containment Isolation Valves B 3.6.3 BASES APPLICABLE The purge valves may be unable to close in the environment following a SAFETY ANALYSES LOCA. Therefore, each of the purge valves is required to remain sealed (continued) closed during MODES 1, 2, 3, and 4.
The containment isolation valves satisfy Criterion 3 of 10 CFR 50.36 (Ref. 3).
LCO Containment isolation valves form a part of the containment boundary. The containment isolation valve safety function is related to minimizing the loss of reactor coolant inventory and establishing the containment boundary during an accident.
The automatic power operated isolation valves are required to have isolation times within limits and to actuate on an automatic isolation signal.
The 48 inch purge valves must be maintained sealed closed. The valves covered by this LCO are listed in the UFSAR (Ref. 4).
The normally closed isolation valves are considered OPERABLE when non-automatic power operated valves are closed, manual valves are closed, check valves have flow through the valve secured, blind flanges are in place, and closed systems are intact.
The containment isolation valve leakage rates are addressed by LCO 3.6.1, "Containment," as Type C testing.
This LCO provides assurance that the containment isolation valves and purge valves will perform their designated safety functions to minimize the loss of reactor coolant inventory and establish the containment boundary during accidents.
APPLICABILITY In MODES 1, 2, 3, and 4, an accident could cause a release of radioactive material to containment. In MODES 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODES. Therefore, the containment isolation valves are not required to be OPERABLE in MODE 5. The requirements for containment isolation valves during MODE 6 are addressed in LCO 3.9.3, "Containment Penetrations."
BASES REVISION DATED 12/18/01 I OCONEE UNITS 1, 2, & 3 B 3.6.3-3
Containment Isolation Valves B 3.6.3 BASES (continued)
ACTIONS The ACTIONS are modified by a Note allowing penetration flow paths, except for 48 inch purge valve penetration flow paths, to be unisolated intermittently under administrative controls. The opening of locked or sealed closed containment isolation valves on an intermittent basis under administrative control includes the following: (1) stationing an operator, who is in constant communication with control room, at the valve controls, (2) instructing this operator to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment (Ref. 5). In this way, the penetration can be rapidly isolated when a need for containment isolation is indicated. Due to the size of the reactor building purge line penetration and the fact that those penetrations exhaust directly from the containment atmosphere to the environment, the penetration flow paths containing these valves may not be opened under administrative controls.
A second Note has been added to provide clarification that, for this LCO, separate Condition entry is allowed for each penetration flow path. This is acceptable, since the Required Actions for each Condition provide appropriate compensatory actions for each inoperable containment isolation valve. Complying with the Required Actions may allow for continued operation, and subsequent inoperable containment isolation valves are governed by subsequent Condition entry and application of associated Required Actions.
The ACTIONS are further modified by a third Note, which ensures appropriate remedial actions are taken, if necessary, if the affected systems are rendered inoperable by an inoperable containment isolation valve.
A.1 and A.2 In the event one containment isolation valve in one or more penetration flow paths is inoperable, the affected penetration flow path must be isolated. The method of isolation must include the use of at least one isolation barrier that cannot be adversely affected by a single active failure.
Isolation barriers that meet this criterion are a closed and de-activated automatic containment isolation valve, a closed and de-activated non automatic power operated valve, a closed manual valve, a blind flange, and a check valve with flow through the valve secured. For a penetration isolated in accordance with Required Action A.1, the device used to isolate the penetration should be the closest available one to containment.
Required Action A.1 must be completed within the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time.
The specified time period is reasonable, considering the time required to isolate the penetration and the relative importance of supporting containment OPERABILITY during MODES 1, 2, 3, and 4.
BASES REVISION DATED 12/18/01 I OCONEE UNITS 1, 2, & 3 B 3.6.3-4
Containment Isolation Valves B 3.6.3 BASES ACTIONS A.1 and A.2 (continued)
For affected penetration flow paths that cannot be restored to OPERABLE status within the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time and that have been isolated in accordance with Required Action A.1, the affected penetration flow paths must be verified to be isolated on a periodic basis. This periodic verification is necessary to ensure that containment penetrations required to be isolated following an accident and no longer capable of being automatically isolated will be in the isolation position should an event occur. This Required Action does not require any testing or device manipulation.
Rather, it involves verification, through a system walkdown, that those isolation devices outside containment and capable of being mispositioned are in the correct position. The Completion Time of "once per 31 days for isolation devices outside containment" is appropriate considering the fact that the devices are operated under administrative controls and the probability of their misalignment is low. The opening of locked or sealed closed containment isolation valves on an intermittent basis under administrative control includes the following: (1) stationing an operator, who is in constant communication with control room, at the valve controls, (2) instructing this operator to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment (Ref. 5). For the isolation devices inside containment, the time period specified as "prior to entering MODE 4 from MODE 5 if not performed within the previous 92 days" is based on engineering judgment and is considered reasonable in view of the inaccessibility of the isolation devices and other administrative controls that will ensure that isolation device misalignment is an unlikely possibility.
Condition A has been modified by a Note indicating this Condition is only applicable to those penetration flow paths with two containment isolation valves. For penetration flow paths with only one containment isolation valve in closed systems, Condition C provides appropriate actions.
Required Action A.2 is modified by a Note that applies to isolation devices located in high radiation areas and allows the devices to be verified by use of administrative means. Allowing verification by administrative means is considered acceptable since access to these areas is typically restricted during MODES 1, 2, 3, and 4 for ALARA reasons. Therefore, the probability of misalignment of these devices, once they have been verified to be in the proper position, is small.
BASES REVISION DATED 12/18/01 I B 3.6.3-5 OCONEE UNITS 1, 2, & 3
Containment Isolation Valves B 3.6.3 BASES ACTIONS B.1 (continued)
With two containment isolation valves in one or more penetration flow paths inoperable, the affected penetration flow path must be isolated within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The method of isolation must include the use of at least one isolatkon barrier that cannot be adversely affected by a single active failure.
Isolation barriers that meet this criterion are a closed and de-activated automatic valve, a closed and de-activated non-automatic power operated valve, a closed manual valve, and a blind flange. A check valve may not be used to isolate the penetration. The 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Completion Time is consistent with the ACTIONS of LCO 3.6.1. In the event the affected penetration is isolated in accordance with Required Action B.1, the affected penetration must be verified to be isolated on a periodic basis per Required Action A.2, which remains in effect. This periodic verification is necessary to assure leak tightness of containment and that penetrations requiring isolation following an accident are isolated. The Completion Time of once per 31 days for verifying each affected penetration flow path is isolated is appropriate considering the fact that the valves are operated under administrative controls and the probability of their misalignment is low. The opening of locked or sealed closed containment isolation valves on an intermittent basis under administrative control includes the following: (1) stationing an operator, who is in constant communication with control room, at the valve controls, (2) instructing this operator to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment (Ref. 5).
Condition B is modified by a Note indicating this Condition is only applicable to penetration flow paths with two containment isolation valves.
Condition A of this LCO addresses the condition of one containment isolation valve inoperable in this type of penetration flow path.
C.1 and C.2 With one or more penetration flow paths with one containment isolation valve inoperable, the inoperable valve must be restored to OPERABLE status or the affected penetration flow path must be isolated. The method of isolation must include the use of at least one isolation barrier that cannot be adversely affected by a single active failure. Isolation barriers that meet this criterion are a closed and de-activated automatic valve, a closed and de-activated non-automatic power operated valve, a closed manual valve, and a blind flange. A check valve may not be used to isolate the affected penetration. Required Action C.1 must be completed within the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time. The specified time period is reasonable, considering the relative stability of the closed system (hence, reliability) to act as a BASES REVISION DATED 12/18/01 I OCONEE UNITS 1, 2, & 3 B 3.6.3-6
Containment Isolation Valves B 3.6.3 BASES ACTIONS C.1 and C.2 (continued) penetration isolation boundary and the relative importance of supporting containment OPERABILITY during MODES 1, 2, 3, and 4. In the event the affected penetration is isolated in accordance with Required Action C.1, the affected penetration flow path must be verified to be isolated on a periodic basis. This periodic verification is necessary to assure leak tightness of containment and that containment penetrations requiring isolation following an accident are isolated. The Completion Time of once per 31 days for verifying that each affected penetration flow path is isolated is appropriate considering the fact that the valves are operated under administrative controls and the probability of their misalignment is low. The opening of locked or sealed closed containment isolation valves on an intermittent basis under administrative control includes the following: (1) stationing an operator, who is in constant communication with control room, at the valve controls, (2) instructing this operator to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment (Ref. 5).
Condition C is modified by a Note indicating that this Condition is only applicable to those penetration flow paths with only one containment isolation valve in closed systems. This Note is necessary since this Condition is written to specifically address those penetration flow paths in a closed system.
Required Action C.2 is modified by a Note that applies to valves and blind flanges located in high radiation areas and allows these devices to be verified by use of administrative means. Allowing verification by administrative means is considered acceptable since access to these areas is typically restricted during MODES 1, 2, 3, and 4 for ALARA reasons.
Therefore, the probability of misalignment of these devices, once verified to be in the proper position, is small.
D.1 and D.2 If the Required Actions and associated Completion Times are not met, the unit must be brought to a MODE in which the LCO does not apply. To achieve this status, the unit must be brought to at least MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and to MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging unit systems.
BASES REVISION DATED 12/18/01 I OCONEE UNITS 1, 2, & 3 B 3.6.3-7
Containment Isolation Valves B 3.6.3 BASES SURVEILLANCE SR 3.6.3.1 REQUIREMENTS Each 48 inch reactor building purge valve is required to be verified sealed closed at 31 day intervals. This Surveillance is designed to ensure that a gross breach of containment is not caused by an inadvertent or spurious opening of a reactor building purge valve. Detailed analysis of the purge valves failed to conclusively demonstrate their ability to close during a LOCA in time to limit offsite doses. Therefore, these valves are required to be in the sealed closed position during MODES 1, 2, 3, and 4. A reactor building purge valve that is sealed closed must have motive power to the valve operator removed. This can be accomplished by de-energizing the source of electric power or by removing the air supply to the valve operator.
In this application, the term "sealed" has no connotation of leak tightness.
The 31 day Frequency is consistent with other containment isolation valve requirements discussed in SR 3.6.3.2.
SR 3.6.3.2 This SR requires verification that each containment isolation manual and non-automatic power operated valve and blind flange located outside containment and not locked, sealed, or otherwise secured, and required to be closed during accident conditions is closed. The SR helps to ensure that post accident leakage of radioactive fluids or gases outside the containment boundary is within design limits. This SR does not require any testing or valve manipulation. Rather, it involves verification, through a system walkdown, that those containment isolation valves outside containment and capable of being mispositioned are in the correct position.
Since verification of valve position for containment isolation valves outside containment is relatively easy, the 31 day Frequency is based on engineering judgment and was chosen to provide added assurance of the correct positions. The SR specifies that containment isolation valves open under administrative controls are not required to meet the SR during the time the valves are open. The opening of locked or sealed closed containment isolation valves on an intermittent basis under administrative control includes the following: (1) stationing an operator, who is in constant communication with control room, at the valve controls, (2) instructing this operator to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment (Ref. 5). The dedicated individual can be responsible for closing more than one valve provided that the valves are all in close vicinity and can be closed in a timely manner. This SR does not apply to valves that are locked, sealed, or otherwise secured, since these were verified to be in the correct position upon locking, sealing, or securing.
BASES REVISION DATED 12/18/01 OCONEE UNITS 1, 2, & 3 B 3.6.3-8
Containment Isolation Valves B 3.6.3 BASES SURVEILLANCE SR 3.6.3.2 (continued)
REQUIREMENTS The Note applies to valves and blind flanges located in high radiation areas and allows these devices to be verified closed by use of administrative means. Allowing verification by administrative means is considered acceptable, since access to these areas is typically restricted during MODES 1, 2, 3, and 4 for ALARA reasons. Therefore, the probability of misalignment of these containment isolation valves, once they have been verified to be in the proper position, is low.
SR 3.6.3.3 This SR requires verification that each containment isolation manual and non-automatic power operated valve and blind flange that is located inside containment and not locked, sealed, or otherwise secured, and required to be closed during accident conditions is closed. The SR helps to ensure that post accident leakage of radioactive fluids or gases outside the containment boundary is within design limits. For containment isolation valves inside containment, the Frequency of "prior to entering MODE 4 from MODE 5 if not performed within the previous 92 days" is appropriate, since these containment isolation valves are operated under administrative controls and the probability of their misalignment is low. The SR specifies that containment isolation valves open under administrative controls are not required to meet the SR during the time they are open. The opening of locked or sealed closed containment isolation valves on an intermittent basis under administrative control includes the following considerations: (1) stationing an operator, who is in constant communication with the control room, at the valve controls, (2) instructing this operator to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment (Ref. 5).
The dedicated individual can be responsible for closing more than one valve provided that the valves are all in close vicinity and can be closed in a timely manner. This SR does not apply to valves that are locked, sealed, or otherwise secured, since these were verified to be in the correct position upon locking, sealing, or securing.
The Note allows valves and blind flanges located in high radiation areas to be verified closed by use of administrative means. Allowing verification by administrative means is considered acceptable, since the access to these areas is typically restricted during MODES 1, 2, 3, and 4 for ALARA reasons. Therefore, the probability of misalignment of these containment isolation valves, once they have been verified to be in their proper position, is small.
BASES REVISION DATED 12/18/01 B 3.6.3-9 OCONEE UNITS 1, 2, & 3
Containment Isolation Valves B 3.6.3 BASES SURVEILLANCE REQUIREMENTS (continued)
SR 3.6.3.4 Verifying that the isolation time of each automatic power operated containment isolation valve is within limits is required to demonstrate OPERABILITY. The isolation time and Frequency of this SR are in accordance with the Inservice Testing Program.
SR 3.6.3.5 Automatic containment isolation valves close on a containment isolation signal to prevent leakage of radioactive material from containment following an accident. This SR ensures that each automatic containment isolation valve will actuate to its isolation position on a containment isolation signal.
This SR is not required for valves that are locked, sealed, or otherwise secured in position under administrative controls. The 18 month Frequency is based on the need to perform this Surveillance under the conditions that apply during a unit outage and the potential for an unplanned transient if the Surveillance were performed with the reactor at power. Operating experience has shown that these components usually pass this Surveillance when performed at the 18 month Frequency. Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.
REFERENCES
- 1.
UFSAR, Section 6.2.
- 2.
UFSAR, Section 15.14.
- 3.
- 4.
UFSAR, Table 6-7.
- 5.
Generic Letter 91-08 BASES REVISION DATED 12/18/01 1 OCONEE UNITS 1, 2, & 3 B 3.6.3-10
Containment Isolation Valves B 3.6.3 BASES (continued)
ACTIONS The ACTIONS are modified by a Note allowing penetration flow paths, except for 48 inch purge valve penetratior4" ths. to be unislated
.,0ermittedy_.und*krJadmiL_
The opening of locked or..
sealed closed containment isolation valves on an intermittent basis under administrative control includes the following: (1) stationing an operator, who is in constant communication with control room, at the valve controls, f (2) instructing this operator to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity,/
outside the containment (Ref. 5).-r-thi' epen rdtioni can be..
o at or-ontainment isolation is indicated. Due to the size of the reactor building purge line penetration and the fact that those penetrations exhaust directly from the containment atmosphere to the environment, the penetration flow paths containing these valves may not be opened under administrative controls.
A second Note has been added to provide clarification that, for this LCO, separate Condition entry is allowed for each penetration flow path. This is acceptable, since the Required Actions for each Condition provide appropriate compensatory actions for each inoperable containment isolation valve. Complying with the Required Actions may allow for continued operation, and subsequent inoperable containment isolation valves are governed by subsequent Condition entry and application of associated Required Actions.
The ACTIONS are further modified by a third Note, which ensures appropriate remedial actions are taken, if necessary, if the affected systems are rendered inoperable by an inoperable containment isolation valve.
A.1 and A.2 In the event one containment isolation valve in one or more penetration flow paths is inoperable, the affected penetration flow path must be isolated. The method of isolation must include the use of at least one isolation barrier that cannot be adversely affected by a single active failure.
Isolation barriers that meet this criterion are a closed and de-activated automatic containment isolation valve, a closed and de-activated non automatic power operated valve, a closed manual valve, a blind flange, and a check valve with flow through the valve secured. For a penetration isolated in accordance with Required Action A.1, the device used to isolate the penetration should be the closest available one to containment.
Required Action A.1 must be completed within the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time.
The specified time period is reasonable, considering the time required to isolate the penetration and the relative importance of supporting containment OPERABILITY during MODES 1, 2, 3, and 4.
BASES REVISION DATED XX/XX/01 I
OCONEE UNITS 1,2, & 3 B 3.6.3-4
Containment Isolation Valves B 3.6.3 BASES ACTIONS A.1 and A.2 (continued)
For affected penetration flow paths that cannot be restored to OPERABLE status within the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time and that have been isolated in accordance with Required Action A.1, the affected penetration flow paths must be verified to be isolated on a periodic basis. This periodic verification is necessary to ensure that containment penetrations required to be isolated following an accident and no longer capable of being automatically isolated will be in the isolation position should an event occur. This Required Action does not require any testing or device manipulation.
Rather, it involves verification, through a system walkdown, that those isolation devices outside containment and capable of being mispositioned are in the correct position. The Completion Time of "once per 31 days for isolation devices outside containment" is appropriate considering the fact that the devices are operated under administrative controls and the p.Igability of
~
n isiris Iowme'opening o locked or sealed closed ntainment isolation valves on an intermittent basis under
-P isolatio administrative control includes the following: (1) stationing an operator, who is in constant communication with control room, at the valve controls, (2) instructing this operator to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment (Ref. 5)fFor the-isolatio-ndevices [
I
"-containment, teie ri6----
ecified as "prior to entering MODE 4 from MODE 5 if not performed within the previous 92 days" is based on engineering judgment and is considered reasonable in view of the inaccessibility of the isolation devices and other administrative controls that will ensure that isolation device misalignment is an unlikely possibility.
Condition A has been modified by a Note indicating this Condition is only applicable to those penetration flow paths with two containment isolation valves. For penetration flow paths with only one containment isolation valve in closed systems, Condition C provides appropriate actions.
Required Action A.2 is modified by a Note that applies to isolation devices located in high radiation areas and allows the devices to be verified by use of administrative means. Allowing verification by administrative means is considered acceptable since access to these areas is typically restricted during MODES 1, 2, 3, and 4 for ALARA reasons. Therefore, the probability of misalignment of these devices, once they have been verified to be in the proper position, is small.
OCONEE UNITS 1, 2, & 3 B 3.6.3-5 BASES REVISION DATEDfl/,.0Op I
Containment Isolation Valves B 3.6.3 BASES ACTIONS B. 1 (continued)
With two containment isolation valves in one or more penetration flow paths inoperable, the affected penetration flow path must be isolated within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The method of isolation must include the use of at least one isolation barrier that cannot be adversely affected by a single active failure.
Isolation barriers that meet this criterion are a closed and de-activated automatic valve, a closed and de-activated non-automatic power operated valve, a closed manual valve, and a biind flange. A check valve may not be used to isolate the penetration. The 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Completion Time is consistent with the ACTIONS of LCO 3.6.1. In the event the affected penetration is isolated in accordance with Required Action B.1, the affected penetration must be verified to be isolated on a periodic basis per Required Action A.2, which remains in effect. This periodic verification is necessary to assure leak tightness of containment and that penetrations requiring isolation following an accident are isolated. The Completion Time of once per 31 days for verifying each affected penetration flow path is isolated is appropriate considering the fact that the valves are operated under i itfive controls andUte b
it f their misalignment is low. /Th 7 opening of locked or sealed closed containment isolation valves on an
\\
7intermittent basis under administrative control includes the following: (1) stationing an operator, who is in constant communication with control room,i at the valve controls, (2) instructing this operator to close these valves in an!
accident situation, and (3) assuring that environmental conditions will not./
preclude access to close the valves and that this action will prevent the
\\
release of radioactivity outside the containment (Ref. 5).
Condition B is modified by a Note indicating this Condition is only applicable to penetration flow paths with two containment isolation valves.
Condition A of this LCO addresses the condition of one containment isolation valve inoperable in this type of penetration flow path.
C.1 and C.2 With one or more penetration flow paths with one containment isolation valve inoperable, the inoperable valve must be restored to OPERABLE status or the affected penetration flow path must be isolated. The method of isolation must include the use of at least one isolation barrier that cannot be adversely affected by a single active failure. Isolation barriers that meet this criterion are a closed and de-activated automatic valve, a closed and de-activated non-automatic power operated valve, a closed manual valve, and a blind flange. A check valve may not be used to isolate the affected penetration. Required Action C.1 must be completed within the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time. The specified time period is reasonable, considering the relative stability of the closed system (hence, reliability) to act as a OCONEE UNITS 1, 2, & 3 B 3.6.3-6 BASES REVISION DATEDD1/34/WO
Containment Isolation Valves B 3.6.3 BASES ACTIONS C.1 and C.2 (continued) penetration isolation boundary and the relative importance of supporting containment OPERABILITY during MODES 1, 2, 3, and 4. In the event the affected penetration is isolated in accordance with Required Action C.1, the affected penetration flow path must be verified to be isolated on a periodic basis. This periodic verification is necessary to assure leak tightness of containment and that containment penetrations requiring isolation following an accident are isolated. The Completion Time of once per 31 days for verifying that each affected penetration flow path is isolated is appropriate considering the fact that the valves are operated under admistrative controls and thep ability of their misalignment is Ilow.
he opening of fclocked or e lscntain-ment 'isola tion val'ves o-n an intermittent
{basis under administrative control includes the following: (1) stationing an
,,!operator, who is inn constant communication with control room, at the valvee radioactivity outside the containment (Ref. 5).
Condition C is modified by a Note indicating that this Condition is only applicable to those penetration flow paths with only one containment isolation valve in closed systems. This Note is necessary since this Condition is written to specifically address those penetration flow paths in a closed system.
Required Action C.2 is modified by a Note that applies to valves and blind flanges located in high radiation areas and allows these devices to be verified by use of administrative means. Allowing verification by administrative means is considered acceptable since access to these areas is typically restricted during MODES 1,2, 3, and 4 for ALARA reasons.
Therefore, the probability of misalignment of these devices, once verified to be in the proper position, is small.
D.1 and D.2 If the Required Actions and associated Completion Times are not met, the unit must be brought to a MODE in which the LCO does not apply. To achieve this status, the unit must be brought to at least MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and to MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the r red unit conditions from full power conditions in an orderly manner and without challenging unit systems.
~x'*
Ix r'~=
I IMIT'£ 1 '*
R.,*B 3 6.3-7 BASES REVISION DATEDA,/I"/0,0 I I
Containment Isolation Valves B 3.6.3 BASES (continued)
SURVEILLANCE REQUI REMENTS SR 3.6.3.2 OCONEE UNITS 1, 2, & 3 B 3.6.3-8 (continued)
This SR requires verification that each containment isolation manual and non-automatic power operated valve and blind flange located outside containment and not locked, sealed, or otherwise secured, and required to be closed during accident conditions is closed. The SR helps to ensure that post accident leakage of radioactive fluids or gases outside the containment boundary is within design limits. This SR does not require any testing or valve manipulation. Rather, it involves verification, through a system walkdown, that those containment isolation valves outside containment and capable of being mispositioned are in the correct position.
Since verification of valve position for containment isolation valves outside containment is relatively easy, the 31 day Frequency is based on engineering judgment and was chosen to pro-vide a dbd-a he olfect positiorns. The SR specifies that containment isolation valves ope-n-,
under administrative controls are not required to meet the SR during the time the valves are open.etrof sst-ef*
4taien"g--deilCaeU 1 11it uIathe'4veive whG~-is'*'n, ti uus
'ammI rlcation.ith te.
The dedicated individual can be S/*
1* responsible for closing more than one valve provided that the valves are all k
in close vicinity and can be closed in a timely manner. This SR does not apply to valves that are locked, sealed, or otherwise secured, sinc9 were verified to be in the correct position up, locking, sealin securing.
The Note applies to vayes ýand blind flanges located in high radiation areas and allows these devices to be verified closed by use of administrative means. Allowing verification by administrative means is considered acceptable, since access to these areas is typically restricted during MODES 1, 2, 3, and 4 for ALARA reasons. Therefore, the probability of misalignment of these containment isolation valves, once they have been verified to be in the proper position, is low.
SR 3.6.3.3 This SR requires verification that each containment isolation manual and non-automatic power operated valve and blind flange that is located inside containment and not locked, sealed, or otherwise secured, and required to be closed during accident conditions is closed. The SR helps to ensure that post accident leakage of radioactive fluids or gases outside the containment boundary is within design limits. For containment isolation valves inside containment, the Frequency of "prior to entering MODE 4 from MODE 5 if not performed within the previous 92 days" is appropriate, since these containment isolation valves are operated under administrative controls and the probability of their misalignment is low. The SR specifies that containment isolation valves open under administrative controls are not BASES REVISION DATE*
Insert-into-SR3.
3o-2 The opening of locked isolation valves on an administrative control
//
considerations:
(1) Si constant communication
- controls, (2) instruct:
valves in an accident environmental conditioi the valves and that th:
radioactivity outside or sealed closed containment intermittent basis under includes the following tationing an operator, who is in with control room, at the valve ing this operator to close these situation, and (3) assuring that as will not preclude access to close is action will prevent the release of the containmentA.
(P'S 5) 1
Containment Isolation Valves B 3.6.3 BASES
\\V SURVEILLANCE REQUIREMENT, SR 3.6.3.3 (continued)
"required to meet the SR during the time they are open.ATý.
admnicstrative eontrd-on, sist 01fstationing a dedie ted idvdala h
.va.lh',
whokr ic in Pontnuio,,
u,..
mm nic tio
- w*-}*
,ith the control r*oom*. The.
dedicated individual can be responsible for closing more than one-valVe
'--crovid-ettre-Wh.cose vicinity.aridLcarn-beclosed in a timely manner. This SR does not apply to valves that are locked, sealed, or otherwise secured, since these were verified to be in the correct position upon locking, sealing, or securing.
The Note allows valves and blind flanges located in high radiation areas to be verified closed by use of administrative means. Allowing verification by administrative means is considered acceptable, since the access to these areas is typically restricted during MODES 1, 2, 3, and 4 for ALARA reasons. Therefore, the probability of misalignment of these containment isolation valves, once they have been verified to be in their proper position, is small.
SR 3.6.3.4 Verifying that the isolation time of each automatic power operated containment isolation valve is within limits is required to demonstrate OPERABILITY. The isolation time and Frequency of this SR are in accordance with the Inservice Testing Program.
SR 3.6.3.5 Automatic containment isolation valves close on a containment isolation signal to prevent leakage of radioactive material from containment following an accident. This SR ensures that each automatic containment isolation valve will actuate to its isolation position on a containment isolation signal.
This SR is not required for valves that are locked, sealed, or otherwise secured in position under administrative controls. The 18 month Frequency is based on the need to perform this Surveillance under the conditions that apply during a unit outage and the potential for an unplanned transient if the Surveillance were performed with the reactor at power. Operating experience has shown that these components usually pass this Surveillance when performed at the 18 month Frequency. Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.
OCONEE UNITS 1, 2, & 3 B 3.6.3-9 BASES REVISION DATED-e-fw=e I
,(
N 9
Insert into
_--6.
_3 The opening of locked or sealed closed containment "isolation valves on an intermittent basis under administrative control includes the following considerations:
(1) stationing an operator, who is in constant communication with control room, at the valve
- controls, (2) instructing this operator to close these valves in an accident situation, and (3) assuring that
/
environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment.
(P-4. 5)
\\
Containment Isolation Valves B 3.6.3 BASES REFERENCES
- 1.
UFSAR, Section 6.2.
- 2.
UFSAR, Section 15.14.
- 3.
- 4.
UFSAR, Table 6-7.
- 5.
6..,-,ez Lt-#ier 91-o8 CB..
3 30 vV S DI OCONEE UNITS 1, 2, & 3 B 3.6.3-10