ML13025A254
| ML13025A254 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 01/21/2013 |
| From: | Gillespie T Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LAR 12-005, Suppl 1 | |
| Download: ML13025A254 (18) | |
Text
T. PRESTON GILLESPIE, Jr.
Enery Vice President 7Energy Oconee Nuclear Station Duke Energy ON01 VP / 7800 Rochester Hwy.
Seneca, SC 29672 864-873-4478 864-873-4208 fax 10 CFR 50.90 T.Gillespie@duke-energy.com January 21, 2013 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001
Subject:
Duke Energy Carolinas, LLC Oconee Nuclear Station, Units 1, 2 and 3 Renewed Facility Operating License Numbers DPR-38, 47 and 55; Docket Numbers 50-269, 50-270 and 50-287; Supplement to License Amendment Request associated with Reverse Osmosis System, License Amendment Request No. 2012-05, Supplement 1 On October 30, 2012, Duke Energy Carolinas, LLC (Duke Energy) submitted a License Amendment Request (LAR) requesting Nuclear Regulatory Commission (NRC) approval to operate a Reverse Osmosis (RO) System to remove silica from the Borated Water Storage Tanks (BWSTs) and Spent Fuel Pools (SFPs) during Unit operation. The LAR also requested approval of associated proposed new Technical Specifications (TSs) and Bases that impose requirements for RO System operation and isolation requirements. By electronic mail dated December 21, 2012, as clarified by a teleconference on January 7, 2013, the NRC requested Duke Energy submit supplemental information to enable the NRC Staff to complete the acceptance review of the LAR. provides the supplemental information. Enclosure 2 provides changes to the proposed Technical Specification and Bases associated with NRC Acceptance Review Issue 1.
The changes were reviewed and approved by the Oconee Plant Operations Review Committee (PORC) on January 16, 2013. The changes proposed by this supplement are bounded by the no significant hazards consideration submitted in the October 30, 2012, LAR.
Inquiries on this submittal should be directed to Boyd Shingleton, Oconee Regulatory Affairs Group, at (864) 873-4716.
I declare under penalty of perjury that the foregoing is true and correct. Executed on January 21, 2013.
Sincerely, T. Preston Gillespie, Jr., Vice President, Oconee Nuclear Station OI www.duke-energy com
U. S. Nuclear Regulatory Commission January 21, 2013 Page 2
Enclosures:
- Duke Energy Response to Acceptance Review Issues - Revised TS and TS Bases
U. S. Nuclear Regulatory Commission January 21, 2013 Page 3 cc w/enclosures:
Mr. Victor McCree, Regional Administrator U. S. Nuclear Regulatory Commission - Region II Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 Mr. John Boska, Project Manager (by electronic mail only)
Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop O-8G9A Rockville, MD 20852-2746 Mr. Eddy Crowe NRC Senior Resident Inspector Oconee Nuclear Site Ms. Susan E. Jenkins, Manager Radioactive & Infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental Control 2600 Bull St.
Columbia, SC 29201
ENCLOSURE 1 License Amendment Request No. 2012-05, Supplement I Duke Energy Response to Acceptance Review Issues
License Amendment Request No. 2011-05, Supplement 1 January 21, 2013 Page 1 Enclosure 1 Duke Energy Response to Acceptance Review Issues NRC Issue 1 An analysis of the impact of a failure to close the boundary valve on the analysis of the limiting single active component failure assumed in the AST analysis.
Duke Energy Response The failure of the single boundary valve to close would result in unacceptable offsite and control room doses. Duke Energy will add a redundant manual isolation valve near the existing Reverse Osmosis (RO) manual isolation valve to eliminate single active failure concerns. This valve will be of an equivalent design as the existing valve. Proposed Technical Specification (TS) 3.7.19, RO System Isolation from BWST, has been revised to require the two RO supply line manual isolation valves to be operable. A note is added to Limiting Condition for Operation (LCO) 3.7.19 to require the BWST Recirculation Pump suction valve to be closed and meet Inservice Testing Program leakage requirements during RO System operation. This requirement is added to prevent post-accident back-leakage from flowing to the top of the BWST when the Spent Fuel Purification Loop piping is aligned for RO System operation on the BWST. Action B has been added to provide appropriate action when two RO System supply manual isolation valves are inoperable (isolate the flow path in one hour). Action C has been added to provide appropriate action when the BWST Recirculation Pump suction valve is discovered not closed or not meeting leakage requirements. SR 3.7.19.1 and 2 have been revised to apply to both RO System supply manual isolation valves. An additional surveillance requirement (SR 3.7.19.3) has been added to require verification that the BWST Recirculation Pump suction valve meets Inservice Testing Program leakage requirements when closed for RO System operation.
Proposed TS Bases 3.7.19 has been revised to reflect these changes. The revised TS and TS Bases pages are provided in Enclosure 2.
Duke Energy evaluated the impact of the addition of the redundant manual isolation valve on the 33 minute time critical operator action (TCOA) credited to isolate the non safety related RO system from the safety related spent fuel purification system. The additional manual valve will be located near the existing manual valve. Since the valves are located in within a few feet of each other, the only impact is the requirement to close two valves rather than one. There is no additional travel time. The time study for closing one valve conservatively assumed 30 seconds for the operator to close; therefore, an additional 60 seconds is assumed for closure of the second valve (30 seconds to move between the first valve and the second and 30 seconds for closure of the second valve). Duke Energy determined it would take 16.8 minutes to close a single valve (refer to Duke Energy letter dated August 2, 2011, Request for Additional Information (RAI) 5 response). This was based on a timeline for isolation of 13 minutes and 25 seconds plus an additional 25%
margin being applied as a conservative measure since the action is not currently in a procedure and only validated with one individual/team. Adding a minute to the 13 minute and 25 second time and an additional 25% (14 minutes 25 seconds + 25%) for conservatism would result in approximately 18 minutes. As such, the addition of another valve that must be closed on event initiation does not have a significant impact on the 33 minute TCOA.
- LAR 2012-05, Supplement 1 January 21, 2013 Page 2 NRC Issue 2 Limitations and controls for the amount of acceptable leakage past the single boundary valve after closure (perhaps a Technical Specification surveillance on the leak rate).
Duke Energy Response Proposed TS 3.7.19 requires the RO Borated Water Storage Tank (BWST) supply side manual isolation valves to be operable in accordance with the Inservice Testing (IST) program. The proposed TS requires the BWST Recirculation Pump suction valve to be closed during RO System operation and meet IST Program leakage requirements. The IST program assigns specific leakage limits. The maximum allowable leakage from the Low Pressure Injection (LPI) System components is currently limited to two gallons per hour (gph). Significant margin (as discussed in response to Issue 3 below) is provided in the Alternative Source Term (AST) calculation to allow for additional leakage. Duke Energy will assign a portion (6 gph maximum) of the additional leakage allowed to the RO System supply manual isolation valves and the BWST Recirculation Pump suction valve. The manual valves are designated as Category A, as defined in Subsection ISTC of the OM Code, to ensure the IST program requires leak rate testing.
NRC Issue 3 An analysis of the impact of any acceptable leakage past the boundary valve after isolation on the AST LOCA analysis.
Duke Energy Response The existing Alternative Source Term (AST) Maximum Hypothetical Accident (MHA) dose analysis assumes 12 gph Emergency Core Cooling System (ECCS) leakage into the auxiliary building. This leakage value is doubled in the calculation to 24 gph in accordance with Regulatory Guide (RG) 1.183. Ten percent of the iodine in the ECCS leakage into the auxiliary building is assumed to become airborne, based on a calculated flash fraction of less than ten percent, and guidance in RG 1.183 Appendix A, Section 5.5.
Any leakage past either boundary valve after isolation could leak to either the auxiliary building or back to the BWST. The release location used for the atmospheric dispersion factor (X/Q) for ECCS leakage to the auxiliary building in the MHA dose analysis is the unit vent. The unit vent XIQ bounds the X/Q for any leakage which would be released from the BWST. Therefore, using the unit vent X/Q for any acceptable RO boundary valve leakage is conservative.
Duke Energy currently limits ECCS leakage to 2 gph, so there is a margin of 10 gph between the current leakage limit and the dose analysis assumption that can be used for RO leakage past the boundary valve after isolation. Ten percent of the iodine in the RO leakage would be assumed to become airborne, which conforms to the NRC guidelines for post Loss of Coolant Accident (LOCA) iodine release in RG 1.183 Appendix A. This model for ECCS leakage was approved in the AST Safety Evaluation for License Amendments 338, 339 and 339 (June 1, 2004).
- LAR 2012-05, Supplement 1 January 21, 2013 Page 3 Therefore, the existing 2 gph for LPI leakage and the maximum 6 gph (refer to the response to issue 2 above) for RO System leakage (for a total of 8 gph) does not impact the AST MHA dose analysis.
NRC Issue 4 Further timing analysis with different operators, to get an average time to close the valve starting from the furthest location the dedicated operator would be allowed to be located.
Duke Energy Response Duke Energy performed the time study for isolating the RO system consistent with Duke Energy procedures and industry standards (reference WCAP-16755-NP, Operator Time Critical Action Program Standard), which requires only one time validation when the completion time is within 80% of the TCOA. The time study determined it would take 16.8 minutes to close a single valve, which was within 80% of the 33 minute TCOA.
In response to the specific NRC issue, Duke Energy performed 3 additional time validations with different operators to obtain an average time to close the valve from the furthest location. Please note that the furthest location is fixed since the operators report to the Control Room and are always dispatched from that location. The time validation was performed for SF-181 since it is slightly further from the Unit 1 & 2 Control Room than 3SF-181 is from the Unit 3 Control Room. The travel times were 2.7 minutes, 2.17 minutes, and 3.0 minutes resulting in an average time to close the valve of 2.62 minutes. As noted in response to NRC Issue 1, an additional quarter turn ball valve will be added within a few feet of SF-181/3SF-181. The new time study conservatively assumes 0.5 minute to travel to the second valve and 0.5 minute to close a second quarter turn valve. Using the worst case travel time of 3.0 minutes, the new time study demonstrates that the time required to isolate the RO System after a LOCA occurs is 14.67 minutes. The additional 25% margin is not applied since the time validation was performed 3 times with different operators.
As stated above, the original time study determined it would take 16.8 minutes to close a single valve (refer to Duke Energy letter dated August 2, 2011, Request for Additional Information (RAI) 5 response). This was based on a timeline for isolation of 13 minutes and 25 seconds plus an additional 25% margin (approximately 3.5 minutes) being applied as a conservative measure since the action is not currently in a procedure and only validated with one individual/team. Only a portion of the time required to close the valve was based on operator travel time to the valve (approximately 3 minutes). Therefore, additional time validations with different operators demonstrated a shorter time to close the valve since the 25% conservatism was removed.
A dedicated operator is not used. Rather, the requirement is driven by the Emergency Operating Procedure (EOP). As stated in the RAI 5 response, within 2 minutes after a LOCA occurs, the EOP has been entered and Immediate Manual Actions and Symptom Checks are complete. At this point, the Senior Reactor Operator (SRO) performs a notification requirement which sends a plant page for an AP/EOP Nuclear Equipment Operator (NEO) to report to the affected unit's control room and all other NEOs report to the affected unit's Control Room. At 10 minutes (the new time study used 10.17 minutes), a
- LAR 2012-05, Supplement 1 January 21, 2013 Page 4 Reactor Operator dispatches an NEO to close SF-181 (time validations were performed for SF-181 and 3SF-181, times for SF-181 were used since it is slightly further away and the times were longer). A stroke time of 30 seconds was conservatively assumed for closing the 2 inch quarter turn ball valve.
NRC Issue 5 Some of the proposed surveillance requirements state the frequency is in accordance with the Surveillance Frequency Control Program (SFCP). Need to provide further bases for why the frequency for the new surveillance can be controlled by the SFCP.
Duke Energy Response Section 2.2 of the Enclosure for the Reverse Osmosis LAR dated October 30, 2012, describes the proposed TS changes for the RO System. Proposed SR 3.7.19.1 and SR 3.9.8.1 specify the Surveillance Requirement (SR) frequencies are in accordance with the Surveillance Frequency Control Program (SFCP). Section 2.2 of the LAR Enclosure provides a 31 day frequency for SR 3.7.19.1 and a 7 day frequency for SR 3.9.8.1.
NRC recently approved an amendment that allowed ONS to relocate certain SR frequencies (as allowed by TSTF 425) to a SFCP. The change allows ONS to change SR frequencies without NRC approval based on an approved method. TSTF 425 allows SR frequencies that are of a fixed frequency to be relocated to a SFCP; except those that reference other approved programs, those that are purely event-driven, those that are event-driven but have a time component for performing the surveillance on a one time basis once the event occurs, or those that are related to specific conditions.
TSTF 425 is applicable to the 7 day and 31 day frequencies of the proposed SRs since they are fixed frequencies and none of the exclusion criteria applies. Therefore, Duke Energy proposes to locate these frequencies in the SFCP.
NRC Issue 6 Explain the logic behind using 33 minutes for switchover to the recirculation mode in the RO LAR based on the fact that the AST analysis assumes switchover occurs at 25 minutes.
Duke Energy Response The minimum time to reach the BWST level where the ECCS sump suction valves are opened is not determined in a mechanistic manner. The minimum TS BWST liquid level is assumed with conservatively high pumped flow rates. The flow rates assumed bound the current plant configuration that includes the LPI cross-tie and Building Spray (BS) flow reduction modifications. No credit is taken for Reactor Coolant System (RCS) or containment pressure greater than atmospheric. The minimum time to deplete the BWST from 46 feet to 9 feet, where the EOP directs the operator to open the ECCS sump suction valves, is 33 minutes.
- LAR 2012-05, Supplement 1 January 21, 2013 Page 5 The value of 25 minutes for transfer to sump recirculation during the AST MHA was maintained as a conservative dose analysis assumption since the flow rates for the AST analysis are based on the design prior to the LPI cross-tie and Building Spray (BS) flow reduction modifications. Using 25 minutes for switchover to sump recirculation mode is conservative for the AST MHA dose analysis because when ECCS leakage is assumed to begin earlier in the accident, more total ECCS leakage is released to contribute to offsite and control room dose.
ENCLOSURE 2 License Amendment Request No. 2012-05, Supplement 1 Revised TS and TS Bases Pages
RO System Isolation from BWST 3.7.19 3.7 Plant Systems 3.7.19 Reverse Osmosis (RO) System Isolation from Borated Water Storage Tank (BWST)
LCO 3.7.19 Two RO System BWST supply manual isolation valves shall be OPERABLE.
NOTE -------------------------
The BWST Recirculation Pump suction valve shall be closed and meet Inservice Testing Program leakage requirements during RO System operation.
APPLICABILITY: MODES 1, 2, 3 and 4 ACTIONS
r, -------------------------------------------------------
Reverse Osmosis flow path may be unisolated intermittently under administrative controls.
CONDITION REQUIRED ACTION COMPLETION TIME A. One supply manual A.1 Isolate the flow path by 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> isolation valve use of at least one inoperable, closed and de-activated automatic valve, one closed and de-activated non-automatic power operated valve, closed manual valve, or blind flange.
AND A.2 Verify the flow path is Once per 31 days isolated.
(continued)
OCONEE UNITS 1, 2, & 3 3.7.19-1 Amendment Nos.
RO System Isolation from BWST 3.7.19 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME B. Two supply manual B.1 Isolate the flow path by 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> isolation valves use of at least one inoperable, closed and de-activated automatic valve, one closed and de-activated non-automatic power operated valve, closed manual valve, or blind flange.
C. BWST Recirculation C.1 Isolate the flow path. 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Pump suction valve not closed or not meeting AND leakage requirements during RO System C.2 Discontinue RO system 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> operation. operation.
D. Required Action and D.1 Be in MODE 3. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> associated Completion Time of Condition A, B AND or C not met.
D.2 Be in MODE 5. 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.19.1 Verify RO System BWST supply manual isolation In accordance with valves that are not locked, sealed, or otherwise the Surveillance secured, are closed, except when the valves are Frequency Control open during RO System operation. Program SR 3.7.19.2 Verify RO System BWST supply manual isolation In accordance with valves are OPERABLE in accordance with the the Inservice Inservice Testing Program. Testing Program SR 3.7.19.3 Verify BWST Recirculation Pump suction valve In accordance with meets Inservice Testing Program Leakage the Inservice Requirements when closed for RO System operation. Testing Program OCONEE UNITS 1, 2, & 3 3.7.19-2 Amendment Nos.
RO System Isolation from BWST B 3.7.19 B 3.7 Plant Systems B 3.7.19 Reverse Osmosis (RO) System Isolation from Borated Water Storage Tank (BWST)
BASES BACKGROUND The RO System removes silica from the Spent Fuel Pools (SFPs) and BWSTs by using a reverse osmosis filtering process.
The RO System, which consists of an RO unit and supply and return piping from the BWSTs and SFPs, is located in the Unit 2 Pipe Trench Area Room (Room 349) directly below the Unit 2 West Penetration Room (WPR). A single RO unit is shared by all three Oconee Nuclear Station (ONS) units. The RO unit is capable of being aligned to the Unit 1 & 2 SFP, the Unit 3 SFP, the Unit 1 BWST, the Unit 2 BWST, or the Unit 3 BWST. RO System piping and existing Spent Fuel (SF) Purification Loop piping are used for these alignments.
To establish a path from the Unit 1 and Unit 2 BWSTs, RO System piping is connected to the Unit 1 & 2 Spent Fuel (SF) Purification Loop. The RO branch line contains two safety related seismically qualified manual isolation valves. Unit 1 & 2 share common manual isolation valves, SF-181 and SF-196. To establish a path from the Unit 3 BWST, RO System piping is connected to the Unit 3 SF Purification Loop. The RO branch line contains two safety related seismically qualified manual isolation valves, 3SF-181 and 3SF-196.
The return piping from the RO unit is routed back to the purification portion of the SF Cooling Systems (Units 1 & 2 and Unit 3). The RO System return piping is non-seismic up to the point where connections are made to the SF purification piping. An isolation valve and a, check valve are installed in series in each of the return lines to the SF purification piping. The check valve and its downstream piping are seismically qualified. BWST Recirculation Pump Suction Valves (SF-57 for Unit 1 & 2 or 3SF-57 for Unit 3) will be closed while the RO System is operating on the respective unit to ensure post-LOCA fluids cannot reach the top of the BWST through the piping as aligned for RO System operation. The location where the discharge piping connects to the purification loop is such that the return flow can be aligned to the same source supplying the RO unit.
The BWST water is routed to the RO System from the SF purification loop. This connection is at a lower elevation than the BWST so a break in the RO System piping will cause the BWST to drain if not isolated.
OCONEE UNITS 1, 2, & 3 B 3.7.19-1 Amendment Nos.
RO System Isolation from BWST B 3.7.19 BASES BACKGROUND Operator action is credited to isolate an RO System piping break. Credit (continued) is also taken for a time critical operator action (TCOA) to isolate the RO system from the BWST by closing the two safety-related manual isolation.
valves to preclude sump back-leakage and ensure the plant stays within the bounds of the design basis loss of coolant accident (LOCA) analysis.
This action is initiated after receipt of an Engineered Safeguards (ES) actuation signal.
APPLICABLE The large break LOCA assumes back-leakage from the sump to the SAFETY ANALYSES borated water storage tank (BWST). Since the RO system takes suction from the BWST, a TCOA is used to isolate the RO system from the BWST at the safety related/non safety related boundary. Additionally, the BWST Recirculation Pump Suction Valve is closed prior to RO system operation to ensure post LOCA back-leakage cannot reach the top of the BWST through the piping as aligned for RO System operation. With the isolation of these pathways, the use of the RO system does not impact the assumptions in the design basis LOCA dose analysis. The TCOA isolates the pathway prior to increasing radiation levels making the location inaccessible and before post-LOCA fluids can reach the BWST.
This operator action, isolation of components that are part of the primary success pathway which functions to mitigate the LOCA, meets 10 CFR 50.36, Criterion 3 (Reference 2). The isolation of the RO system credits two safety related manual isolation valves to ensure the plant stays within the bounds of the design basis LOCA analysis.
LCO This LCO requires that the two manual isolation valves (SF-181 and SF-196 for Unit 1 and 2 and 3SF-181 and 3SF-196 for Unit 3) used to isolate the RO System from BWST to be OPERABLE. The valves are considered OPERABLE when they are closed or capable of being closed prior to initiation of ECCS -recirculation. The LCO is modified by a note indicating that the BWST Recirculation Pump Suction Valve (SF-57 for Unit 1 & 2 or 3SF-57 for Unit 3) shall be closed and meet Inservice Testing Program leakage requirements while the RO System is in operation to ensure post-LOCA fluids cannot reach the top of the BWST as a result of the piping alignment during RO System operation APPLICABILITY The RO System isolation valves are required to be OPERABLE in MODES 1, 2, 3, and 4, consistent with emergency core cooling system (ECCS) recirculation OPERABILITY requirements. The RO System isolation valves must be OPERABLE to ensure the plant stays within the bounds of the design basis LOCA analysis.
OCONEE UNITS 1, 2, & 3 B 3.7.19-2 Amendment Nos.
RO System Isolation from BWST B 3.7.19 BASES (continued)
ACTIONS The ACTIONS are modified by a Note allowing the RO System flow path to be unisolated intermittently under administrative controls. The opening of a closed valve in the RO System flow path 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 RO System. In this way, the flow path can be rapidly isolated when a need for isolation is indicated.
A.1 and A.2 In the event one RO System BWST supply manual isolation valve is inoperable, the flow path must be isolated within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 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 isolation valve, a closed and de-activated non-automatic power operated valve, a closed manual valve, or a blind flange. For the RO System flow path isolated in accordance with Required Action A.1, the device used to isolate the flow path should be the closest available to the inoperable RO System BWST supply isolation valve. The 4-hour Completion Time is considered reasonable, considering the time required to isolate the flow path and the low probability of an accident occurring during this time period requiring isolation of the RO system from the BWST.
For a manual isolation valve 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 has been isolated in accordance with Required Action A.1, the flow path must be verified to be isolated on a periodic basis. This periodic verification is necessary to ensure that the flow path is isolated should an event occur requiring it to be isolated. This Required Action does not require any testing or device manipulation. Rather, it involves verification, through a system walkdown, that an isolation device capable of being mispositioned is in the correct position. The Completion Time of "once per 31 days" is appropriate considering the fact that the device is operated under administrative controls and the probability of its misalignment is low.
OCONEE UNITS 1, 2, & 3 B 3.7.19-3 Amendment Nos.
RO System Isolation from BWST B 3.7.19 BASES ACTIONS B. 1 (continued)
In the event two RO System BWST supply manual isolation valves are inoperable, the 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 isolation valve, a closed and de-activated non-automatic power operated valve, a closed manual valve, or a blind flange. For the RO System flow path isolated in accordance with Required Action B.1, the device used to isolate the flow path should be the closest available to the RO System BWST supply manual isolation valves. The 1-hour Completion Time is considered reasonable, considering the time required to isolate the flow path and the low probability of an accident occurring during this time period requiring isolation of the RO system from the BWST.
In the event the affected RO System flow path is isolated in accordance with Required Action B.1, the flow path 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 ensure that the flow path is isolated should an event occur requiring it to be isolated. The Completion Time of once per 31 days for verifying the flow path is isolated is appropriate considering the fact that the device is operated under administrative controls and the probability of its misalignment is low.
C.1 and C.2 In the event the RO System is operating and the BWST Recirculation Pump suction valve is discovered not closed or it is determined the Inservice Testing (IST) Program leakage requirements are not met, the flow path must be isolated and RO system operation must be discontinued within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The 1-hour Completion Time is considered reasonable, considering the time required to isolate the flow path and discontinue RO System operation and the low probability of an accident occurring during the time period requiring this action. If the suction valve is discovered not closed, the requirement is to isolate the flow path with the suction valve. In this case, the requirements of the LCO are met and the Condition no longer applies. However, if the suction valve is discovered to not meet IST Program leakage requirements, the flow path must be isolated and RO System operation must be discontinued. This is necessary to ensure that the flow path to the top of the BWST is isolated.
OCONEE UNITS 1, 2, & 3 B 3.7.19-4 Amendment Nos.
RO System Isolation from BWST B 3.7.19 BASES ACTIONS D.1 and D.2 (continued)
If the Required Actions and associated Completion Times of Condition A, B, or C 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.
SURVEILLANCE SR 3.7.19.1 REQUIREMENTS This SR requires verification that RO System BWST manual isolation valves (SF-181 and SF-1 96 for Unit 1 & 2 and 3SF-181 and 3SF-1 96 for Unit 3) not locked, sealed, or otherwise secured in the closed position, are closed. The SR helps to ensure that post accident leakage of radioactive fluids do not impact the offsite dose analysis. This SR does not require any testing or valve manipulation. Rather, it involves verification, through a system walkdown, that each manual isolation valve is closed. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. The SR specifies that the manual isolation valve is not required to be closed during RO System operation. During the time period the manual isolation valves are open, a TCOA is credited to close the valves should an accident occur requiring isolation of the flow path. This SR does not apply if a valve is locked, sealed, or otherwise secured, since it was verified to be in the correct position upon locking, sealing, or securing.
SR 3.7.19.2 This SR verifies that the RO System supply manual isolation valves (SF-181 and SF-196 for Unit 1 & 2 and 3SF-181 and 3SF-196 for Unit 3) that are used to isolate the BWST from the RO System are OPERABLE in accordance with the Inservice Testing Program. The specified Frequency is in accordance with the Inservice Testing Program requirements.
OCONEE UNITS 1, 2, & 3 B 3.7.19-5 Amendment Nos.
a RO System Isolation from BWST B 3.7.19 BASES SURVEILLANCE SR 3.7.19.3 REQUIREMENTS (continued) This SR verifies that the BWST Recirculation Pump suction valve (SF-57 for Unit 1 & 2 or 3SF-57 for Unit 3) meets Inservice Testing Program leakage requirements when closed for RO System operation. The specified frequency is in accordance with the Inservice Testing Program requirements.
REFERENCES 1. UFSAR, Section 9.1.3.
- 2. 10 CFR 50.36.
OCONEE UNITS 1, 2, & 3 B 3.7.19-6 Amendment Nos.