NL-19-1248, Revise Technical Specification Requirements During Handling Irradiated Fuel and Core Alterations - TSTF-51, SNC Response to NRC Request for Additional Information
| ML19290E958 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 10/17/2019 |
| From: | Gayheart C Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-19-1248 | |
| Download: ML19290E958 (23) | |
Text
~ Southern Nuclear Cheryl A. Gayheart Regulatory Affairs Director 3535 Colonnade Parkway Birmingham, AL 35243 205 992 5316 tel 205 992 7601 fax cagayhea@ southernco.com OCT 1 7 2019 Docket Nos. : 50-321 NL-19-1248 50-366 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant Units 1 and 2 Revise Technical Specification Requirements During Handling Irradiated Fuel and Core Alterations - TSTF-51 SNC Response to NRC Request for Additional Information Ladies and Gentlemen:
By letter dated April 24, 2019 (Agencywide Documents Access and Management System Accession Number ML19114A456), Southern Nuclear Operating Company (SNC) submitted a license amendment request (LAR) for the Edwin I. Hatch Nuclear Plant (HNP), Units 1 and 2.
This LAR requested adoption of TSTF-51-A, Revision 2, "Revise Containment Requirements During Handling Irradiated Fuel and Core Alterations."
By email dated October 4, 2019, the U.S. Nuclear Regulatory Commission (NRC) staff notified SNC that additional information is needed for the staff to complete their review. Enclosure 1 to this letter provides the SNC response to the NRC request for additional information (RAI). provides associated marked-up technical specification (TS) pages. Enclosure 3 provides clean-typed TS pages. Enclosure 4 provides applicable TS Bases pages marked to show the proposed changes for information only.
The conclusions of the No Significant Hazards Consideration and Environmental Consideration contained in the original LAR have been reviewed and are unaffected by this RAI response.
This letter contains no NRC commitments. If you have any questions, please contact Jamie Coleman at 205.992.6611.
U. S. Nuclear Regulatory Commission NL-19-1248 Page 2 I declare under penalty of perjury that the foregoing is true and correct. Executed on the 111h.- day of October 2019.
Respectfully submitted, Cheryl A. Gayheart Director, Regulatory Affairs Southern Nuclear Operating Company CAG/tle/sm
Enclosures:
- 2. Technical Specification Marked-up Pages
- 3. Technical Specification Clean-typed Pages
- 4. Technical Specification Bases Marked-up Pages (For Information Only) cc: Regional Administrator, Region II NRR Project Manager- Hatch Senior Resident Inspector - Hatch Director, Environmental Protection Division - State of Georgia RType: CHA02.004
Edwin I. Hatch Nuclear Plant Units 1 and 2 Revise Technical Specification Requirements During Handling Irradiated Fuel and Core Alterations- TSTF-51 SNC Response to NRC Request for Additional Information Enclosure 1 SNC Response to NRC RAI to NL-19-1248 SNC Response to NRC RAI NRC RAI By letter dated April24, 2019, Southern Nuclear Operating Company, Inc. (SNC, the licensee) submitted a license amendment request for the Edwin I. Hatch Nuclear Plant (HNP), Units 1 and 2, (Agencywide Documents Access and Management System Accession No. ML19114A456; EPID L-2019-LLA-0091) to revise certain Technical Specifications (TSs) to remove the requirements for engineered safety feature systems (e.g., secondary containment, secondary containment valve isolation capability, and standby gas treatment system) to be operable after sufficient radioactive decay of irradiated fuel has occurred following a plant shutdown.
The NRC staff has reviewed your application and has determined that additional information is needed to complete its review.
1.0 Regulatory Evaluation The regulation 10 CFR 30.36 states:
(2) Limiting conditions for operation. (i) Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility. When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met. When a limiting condition for operation of any process step in the system of a fuel reprocessing plant is not met, the licensee shall shut down that part of the operation or follow any remedial action permitted by the technical specifications until the condition can be met. In the case of a nuclear reactor not licensed under§ 50.21 (b) or§ 50.22 of this part or fuel reprocessing plant, the licensee shall notify the Commission, review the matter, and record the results of the review, including the cause of the condition and the basis for corrective action taken to preclude recurrence. The licensee shall retain the record of the results of each review until the Commission terminates the license for the nuclear reactor or the fuel reprocessing plant. In the case of nuclear power reactors licensed under§ 50.21 (b) or§ 50.22, the licensee shall notify the Commission if required by§ 50.72 and shall submit a Licensee Event Report to the Commission as required by§ 50.73. In this case, licensees shall retain records associated with preparation of a Licensee Event Report for a period of three years following issuance of the report. For events which do not require a Licensee Event Report, the licensee shall retain each record as required by the technical specifications.
(ii) A technical specification limiting condition for operation of a nuclear reactor must be established for each item meeting one or more of the following criteria:
(A) Criterion 1. Installed instrumentation that is used to detect, and indicate in the control room, a significant abnormal degradation of the reactor coolant pressure boundary.
(B) Criterion 2. A process variable, design feature, or operating restriction that is an initial condition of a design basis accident or transient analysis that either assumes the failure of or presents a challenge to the integrity of a fission product barrier.
E1-1 to NL-19-1248 SNC Response to NRC RAI (C) Criterion 3. A structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier.
(D) Criterion 4. A structure, system, or component which operating experience or probabilistic risk assessment has shown to be significant to public health and safety.
2.0 Request for Additional Information By letter dated September 4, 2019 (ADAMS Accession No. ML 19198AA104), the NRC issued Amendment Nos. 298 and 243 to HNP, Units 1 and 2, respectively. Amendment No. 298 changed TS pages 3.6-34 through 3.6-36 for HNP, Unit 1. Amendment No. 243 changed TS pages 3.6-33 through 3.6-35 for HNP, Unit 2.
By letter dated April 24, 2019, SNC provided marked up TS pages 3.6-34 and 3.6-35 for HNP, Unit 1, and TS pages 3.6-33 and TS 3.6-34 for HNP, Unit 2 in Attachment 1. These TS pages contained in the letter dated April 24, 2019, no longer represent the current TS authority file.
Please supplement the letter dated April 24, 2019, with the correct TS authority file TS pages marked up.
SNC Response to RAI The requested TS markup pages 3.6-34 and 3.6-35 for Unit 1, and 3.6-33 and 3.6-34 are provided in Enclosure 2. Clean-typed pages for these markups are provided in Enclosure 3.
Applicable TS Bases markups, as tracked changes, are provided for information in Enclosure 4.
Note that because of changes due to Amendments 298 for Unit 1 and 243 for Unit 2, the TS Bases page numbers are different than those originally provided in the SNC letter dated April 24, 2019.
E1-2
Edwin I. Hatch Nuclear Plant Units 1 and 2 Revise Technical Specification Requirements During Handling Irradiated Fuel and Core Alterations- TSTF-51 SNC Response to NRC Request for Additional Information Enclosure 2 Technical Specification Marked-up Pages
Secondary Containment 3.6.4.1 3.6 CONTAINMENT SYSTEMS 3.6.4.1 Secondary Containment LCO 3.6.4.1 The secondary containment shall be OPERABLE.
~
tj o
APPLICABILITY: MODES 1 21 and 31 I ~
During movement of Irradiated fuel assemblies in the secondary containment,~
During CORE /\LTER/\TION8.
- ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Secondary containment A.1 Verify secondary 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> inoperable in MODE 1 2 1 I containment vacuum of or 3 due to SR 3.6.4.1.3 not <!: 0.20 inch water gauge met. can be established in s 10 minutes using one or more OPERABLE standby gas treatment (SGT) subsystem(s}.
AND A.2 Restore secondary 7 days containment to OPERABLE status.
B. Secondary containment B.1 Verify secondary 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> inoperable in MODE 1 2 1 I containment vacuum of or 3 due to SR 3.6.4.1.4 not <!: 0.20 inch water gauge met. can be maintained for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> using one or more OPERABLE SGT subsystem(s) at a flow rate s 4000 cfm per subsystem .
AND B.2 Restore secondary 7 days containment to OPERABLE status.
(continued)
HATCH UNIT 1 3.6-34 Amendment No. 298
Secondary Containment 3.6.4.1 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME C. Secondary containment C. 1 Restore secondary 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> inoperable in MODE 1, 2, containment to or 3 for reasons other than OPERABLE status.
Condition A or B.
D. Required Action and D.1 ------------NOTE---------
associated Completion LCO 3.0.4.a is not Time of Condition A, B, or C applicable when not met. entering MODE 3.
r{ recently 3 Be in MODE 3. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> E. Secondary cc ntainment E.1 ----------NOTE---------
inoperable ~ring LCO 3.0.3 is not movement o ~~radiated fuel applicable.
assemblies in the --------------------------------
secondary containment--ef eh:IFiRJ GGRE Suspend movement of Immediately ALTERATIGN8. irradiated fuel f recently 1 assemblies in the secondary containment.
AN9 H 81:JSj3eRa GQRE lmmeaiately Al=FERA=FIGN8.
HATCH UNIT 1 3.6-35 Amendment No. 298
Secondary Containment 3.6.4.1 3.6 CONTAINMENT SYSTEMS 3.6.4.1 Secondary Containment LCO 3.6.4.1 The secondary containment shall be OPERABLE.
~
o APPLICABILITY: MODES 1, 2, and 3, During movement ofWra~ssemblies in the secondary containment,~
During GORE ALTERATIONS.
- ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Secondary containment A.1 Verify secondary 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> inoperable in MODE 1, 2, containment vacuum of or 3 due to SR 3.6.4.1.3 not ~ 0.20 inch water gauge met. can be established in !:>
10 minutes using one or more OPERABLE standby gas treatment (SGT) subsystem(s).
AND A.2 Restore secondary 7 days containment to OPERABLE status.
B. Secondary containment B.1 Verify secondary 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> inoperable in MODE 1, 2, containment vacuum of or 3 due to SR 3.6.4.1.4 not ~ 0.20 inch water gauge met. can be maintained for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> using one or more OPERABLE SGT subsystem(s) at a flow rate !:> 4000 cfm per subsystem.
AND B.2 Restore secondary 7 days containment to OPERABLE status.
(continued)
HATCH UNIT2 3.6-33 Amendment No. 2-43
Secondary Containment 3.6.4.1 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME C. Secondary containment C. 1 Restore secondary 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> inoperable in MODE 1, 2, containment to or 3 for reasons other than OPERABLE status.
Condition A or B.
D. Required Action and D.1 ------------NOTE---------
associated Completion LCO 3.0.4.a is not Time of Condition A, B, or applicable when C not met. entering MODE 3.
r{ recently 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 /> E. Secondary co htainment E.1 -----------NOTE------------
inoperable du ing LCO 3.0 .3 is not movement ot\~radiated fuel applicable.
assemblies in the -------------------------------
secondary containment:-GF SI::IFiA§ GQRE Suspend movement of Immediately ALTERATIQNS . irradiated fuel assemblies in the t recently ; secondary containment.
ANQ
~ SI::ISJ3eA8 GQRE lmmeaiately ALTERATIQNS.
HATCH UNIT 2 3.6-34 Amendment No. ~
Edwin I. Hatch Nuclear Plant Units 1 and 2 Revise Technical Specification Requirements During Handling Irradiated Fuel and Core Alterations- TSTF-51 SNC Response to NRC Request for Additional Information Enclosure 3 Technical Specification Clean-typed Pages
Secondary Containment 3.6.4.1 3.6 CONTAINMENT SYSTEMS 3.6.4.1 Secondary Containment LCO 3.6.4.1 The secondary containment shall be OPERABLE.
APPLICABILITY: MODES 1, 2, and 3, During movement of recently irradiated fuel assemblies in the secondary containment.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Secondary containment A. 1 Verify secondary 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> inoperable in MODE 1, 2, containment vacuum of or 3 due to SR 3.6.4.1.3 not ~ 0.20 inch water gauge met. can be established in s 10 minutes using one or more OPERABLE standby gas treatment (SGT) subsystem(s).
AND A.2 Restore secondary 7 days containment to OPERABLE status.
B. Secondary containment B.1 Verify secondary 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> inoperable in MODE 1, 2, containment vacuum of or 3 due to SR 3.6.4.1.4 not ~ 0.20 inch water gauge met. can be maintained for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> using one or more OPERABLE SGT subsystem(s) at a flow rate s 4000 cfm per subsystem.
AND B.2 Restore secondary 7 days containment to OPERABLE status.
(continued)
HATCH UNIT 1 3.6-34 Amendment No.
Secondary Containment 3.6.4 .1 ACTIONS(continued)
CONDITION REQUIRED ACTION COMPLETION TIME C. Secondary containment C. 1 Restore secondary 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> inoperable in MODE 1, 2, containment to or 3 for reasons other than OPERABLE status.
Condition A or B.
D. Required Action and D.1 ------------NOTE---------
associated Completion LCO 3.0.4.a is not Time of Condition A, B, or C applicable when not met. entering MODE 3.
Be in MODE 3. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> E. Secondary containment E.1 ------------NOTE-----------
inoperable during LCO 3.0.3 is not movement of recently applicable.
irradiated fuel assemblies in --------------------------------
Suspend movement of Immediately recently irradiated fuel assemblies in the secondary containment.
HATCH UNIT 1 3.6-35 Amendment No.
Secondary Containment 3.6.4.1 3.6 CONTAINMENT SYSTEMS 3.6.4.1 Secondary Containment LCO 3.6.4.1 The secondary containment shall be OPERABLE.
APPLICABILITY: MODES 1, 2, and 3, During movement of recently irradiated fuel assemblies in the secondary containment.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Secondary containment A.1 Verify secondary 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> inoperable in MODE 1, 2, containment vacuum of or 3 due to SR 3.6.4.1.3 not ~ 0.20 inch water gauge met. can be established in s 10 minutes using one or more OPERABLE standby gas treatment (SGT) subsystem(s) .
AND A.2 Restore secondary 7 days containment to OPERABLE status.
B. Secondary containment B.1 Verify secondary 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> inoperable in MODE 1, 2, containment vacuum of or 3 due to SR 3.6.4.1.4 not ~ 0.20 inch water gauge met. can be maintained for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> using one or more OPERABLE SGT subsystem(s) at a flow rate s 4000 cfm per subsystem .
AND B.2 Restore secondary 7 days containment to OPERABLE status.
(contmued)
HATCH UNIT 2 3.6-33 Amendment No.
Secondary Containment 3.6.4.1 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME C. Secondary containment C.1 Restore secondary 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> inoperable in MODE 1, 2, containment to or 3 for reasons other than OPERABLE status.
Condition A or B.
D. Required Action and D.1 ------------NOTE---------
associated Completion LCO 3.0.4.a is not Time of Condition A, B, or applicable when C not met. entering MODE 3.
Be in MODE 3. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> E. Secondary containment E.1 -----------NOTE------------
inoperable during LCO 3.0.3 is not movement of recently applicable.
irradiated fuel assemblies -------------------------------
in the secondary containment. Suspend movement of Immediately recently irradiated fuel assemblies in the secondary containment.
HATCH UNIT2 3.6-34 Amendment No.
Edwin I. Hatch Nuclear Plant Units 1 and 2 Revise Technical Specification Requirements During Handling Irradiated Fuel and Core Alterations- TSTF-51 SNC Response to NRC Request for Additional Information Enclosure 4 Technical Specification Bases Marked-up Pages (For Information Only)
Secondary Containment B 3.6.4.1 BASES BACKGROUND a. All hatches separating Zone Ill from Zone I are closed and (continued) sealed; and
- b. At least one door in each access path separating Zone Ill from Zone I is closed.
To prevent ground level exfiltration while allowing the secondary containment to be designed as a conventional structure, the secondary containment requires support systems to maintain the control volume pressure at less than the external pressure.
Requirements for these systems are specified separately in LCO 3.6.4.2, "Secondary Containment Isolation Valves (SCIVs)," and LCO 3.6.4.3, "Standby Gas Treatment (SGT) System." When one or more zones are excluded from secondary containment, the specific requirements for the support systems will also change (e.g., securing particular SGT or drain isolation valves).
APPLICABLE There are two principal accidents for which credit is taken for SAFETY ANALYSES secondary containment OPERABILITY. These are a loss of coolant accident (LOCA) (Ref. 1) and a fuel handling accident involving handling recently irradiated fuel (i.e., fuel that has occupied part of a critical reactor core within the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) inside secondary containment (Ref. 2). The secondary containment performs no active function in response to either of these limiting events; however, its leak tightness is required to ensure that the release of radioactive materials from the primary containment is restricted to those leakage paths and associated leakage rates assumed in the accident analysis and that fission products entrapped within the secondary containment structure will be treated by the Unit 1 and Unit 2 SGT Systems prior to discharge to the environment. Postulated LOCA leakage paths from the primary containment into secondary containment include those into both the reactor building and refueling floor areas (e.g., drywell head leakage) .
Secondary containment satisfies Criterion 3 of the NRC Policy Statement (Ref. 4).
LCO An OPERABLE secondary containment provides a control volume into which fission products that bypass or leak from primary containment, or are released from the reactor coolant pressure boundary (continued)
HATCH UNIT 1 B 3.6-82 REVISION +Gd
Secondary Containment B 3.6.4.1 BASES LCO components located in secondary containment, can be diluted and (continued) processed prior to release to the environment. For the secondary containment to be considered OPERABLE, it must have adequate leak tightness to ensure that the required vacuum (0.20 inch of vacuum) can be established and maintained. The secondary containment boundary required to be OPERABLE is dependent on the operating status of both units, as well as the configuration of doors, hatches, refueling floor plugs, SCIVs, and available flow paths to SGT Systems. The required boundary encompasses the zones which can be postulated to contain fission products from accidents required to be considered for the Condition of each unit, and furthermore, must include zones not isolated from the SGT subsystems being credited for meeting LCO 3.6.4.3. Allowed configurations, associated SGT subsystem requirements, and associated SCIV requirements are detailed in the Technical Requirements Manual (Ref. 3).
APPLICABILITY In MODES 1, 2, and 3, a LOCA could lead to a fission product release to primary containment that leaks to secondary containment (the reactor building zone and potentially the refueling floor zone).
Therefore, secondary containment OPERABILITY is required during the same operating conditions that require primary containment OPERABILITY.
In MODES 4 and 5, the probability and consequences of the LOCA are reduced due to the pressure and temperature limitations in these MODES. Therefore, maintaining secondary containment OPERABLE is not required in MODE 4 or 5 to ensure a control volume, except for other situations for which significant releases of radioactive material can be postulated, such as during CORE ALTERATIONS, or during movement of recently irradiated fuel assemblies in the secondary containment. (Note: Moving irradiated fuel assemblies in tho secondary containment may also occur in MODES 1, 2, and 3.) Due to radioactive decay, secondary containment is only required to be OPERABLE during fuel handling involving handling recently irradiated fuel (i.e., fuel that has occupied part of a critical reactor core within the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />). Since CORE ALTERAT I O~lS and movement of recently irradiated fuel assemblies are only postulated to release radioactive material to the refueling floor zone, the secondary containment configuration may consist of only Zone Ill during tAese this conditions.
(continued)
HATCH UNIT 1 B 3.6-83 REVISION +Gd
Secondary Containment B 3.6.4.1 BASES ACTIONS E.1 and E.2 (continued)
Movement of recently irradiated fuel assemblies in the secondary containment and CORE ALTERATIONS can be postulated to cause significant fission product release to the secondary containment. In such g_cases, the secondary containment is the only barrier to release of fission products to the environment. CORE ALTERATIONS aooTherefore, movement of recently irradiated fuel assemblies must be immediately suspended if the secondary containment is inoperable.
Suspension of tResethis acti'litiesactivity shall not preclude completing an action that involves moving a component to a safe position.
Required Action E.1 has been modified by a Note stating that LCO 3.0.3 is not applicable. If moving recently irradiated fuel assemblies while in MODE 4 or 5, LCO 3.0.3 would not specify any action. If moving recently irradiated fuel assemblies while in MODE 1, 2, or 3, the fuel movement is independent of reactor operations.
Therefore, in either case, inability to suspend movement of recently irradiated fuel assemblies would not be a sufficient reason to require a reactor shutdown.
SURVEILLANCE SR 3.6.4.1.1 REQUIREMENTS Verifying that secondary containment equipment hatches are closed ensures that the infiltration of outside air of such a magnitude as to prevent maintaining the desired negative pressure does not occur and provides adequate assurance that exfiltration from the secondary containment will not occur. SR 3.6.4.1.1 also requires equipment hatches to be sealed. In this application, the term "sealed" has no connotation of leak tightness. When the secondary containment configuration excludes Zone I and/or Zone II, this SR also includes verifying the hatches separating the common refueling floor zone from the reactor building(s). The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
SR 3.6.4.1.2 Verifying that one secondary containment access door in each access opening is closed provides adequate assurance that exfiltration from the secondary containment will not occur. An access opening contains one inner and one outer door. The intent is to not breach the secondary containment, which is achieved by maintaining the inner or outer portion of the barrier closed except when the access opening is being used for entry and exit. The phrase "being used for entry and exit" ensures the time both doors may be open simultaneously is limited to the time it takes to traverse through a door, which is insignificant. When the secondary containment configuration (continued)
HATCH UNIT 1 B 3.6-86 REVISION +Ga
Secondary Containment B 3.6.4.1 BASES BACKGROUND a. All hatches separating Zone Ill from Zone II are closed and (continued) sealed; and
- b. At least one door in each access path separating Zone Ill from Zone II is closed.
To prevent ground level exfiltration while allowing the secondary containment to be designed as a conventional structure, the secondary containment requires support systems to maintain the control volume pressure at less than the external pressure.
Requirements for these systems are specified separately in LCO 3.6.4.2, "Secondary Containment Isolation Valves (SCIVs)," and LCO 3.6.4.3, "Standby Gas Treatment (SGT) System." When one or more zones are excluded from secondary containment, the specific requirements for the support systems will also change (e.g., securing particular SGT or drain isolation valves).
APPLICABLE There are two principal accidents for which credit is taken for SAFETY ANALYSES secondary containment OPERABILITY. These are a loss of coolant accident (LOCA) (Ref. 1) and a fuel handling accident involving handling recently irradiated fuel (i.e., fuel that has occupied part of a critical reactor core within the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) inside secondary containment (Ref. 2). The secondary containment performs no active function in response to either of these limiting events; however, its leak tightness is required to ensure that the release of radioactive materials from the primary containment is restricted to those leakage paths and associated leakage rates assumed in the accident analysis and that fission products entrapped within the secondary containment structure will be treated by the Unit 1 and Unit 2 SGT Systems prior to discharge to the environment. Postulated LOCA leakage paths from the primary containment into secondary containment include those into both the reactor building and refueling floor zones (e.g., drywell head leakage).
Secondary containment satisfies Criterion 3 of the NRC Policy Statement (Ref. 4).
LCO An OPERABLE secondary containment provides a control volume into which fission products that bypass or leak from primary containment, or are released from the reactor coolant pressure boundary (continued)
HATCH UNIT 2 B 3.6-84 REVISION .:1-+Q
Secondary Containment B 3.6.4.1 BASES LCO components located in secondary containment, can be diluted and (continued) processed prior to release to the environment. For the secondary containment to be considered OPERABLE, it must have adequate leak tightness to ensure that the required vacuum (0.20 inch of vacuum) can be established and maintained. The secondary containment boundary required to be OPERABLE is dependent on the operating status of both units, as well as the configuration of doors, hatches, refueling floor plugs, SCIVs, and available flow paths to SGT Systems.
The required boundary encompasses the zones which can be postulated to contain fission products from accidents required to be considered for the condition of each unit, and furthermore, must include zones not isolated from the SGT subsystems being credited for meeting LCO 3.6.4.3. Allowed configurations, associated SGT subsystem requirements, and associated SCIV requirements are detailed in the Technical Requirements Manual (Ref. 3).
APPLICABILITY In MODES 1, 2, and 3, a LOCA could lead to a fission product release to primary containment that leaks to secondary containment (the reactor building zone and potentially the refueling floor zone).
Therefore, secondary containment OPERABILITY is required during the same operating conditions that require primary containment OPERABILITY.
In MODES 4 and 5, the probability and consequences of the LOCA are reduced due to the pressure and temperature limitations in these MODES. Therefore, maintaining secondary containment OPERABLE is not required in MODE 4 or 5 to ensure a control volume, except for other situations for which significant releases of radioactive material can be postulated, such as during CORE ALTERATIONS , or during movement of recently irradiated fuel assemblies in the secondary containment. (Note, moving irradiated fuel assemblies in the secondary containment may also occur in MODES 1, 2, and 3.) Due to radioactive decay, secondary containment is only required to be OPERABLE during fuel handling involving handling recently irradiated fuel (i.e., fuel that has occupied part of a critical reactor core within the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />). Since CORE ALTERATIONS and movement of recently irradiated fuel assemblies are only postulated to release radioactive material to the refueling floor zone, the secondary containment configuration may consist of only Zone Ill during tRese this conditions.
(continued)
HATCH UNIT 2 B 3.6-85 REVISION .:t-:1-G
Secondary Containment B 3.6.4.1 BASES ACTIONS C.1 (continued)
Conditions A or B, it must be restored to OPERABLE status within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time provides a period of time to correct the problem that is commensurate with the importance of maintaining secondary containment during MODES 1, 2, and 3. This time period also ensures that the probability of an accident (requiring secondary containment OPERABILITY) occurring during periods where secondary containment is inoperable is minimal.
If secondary containment cannot be restored to OPERABLE status within the required Completion Time, the plant must be brought to a MODE in which overall plant risk is minimized. To achieve this status, the plant 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 />.
Remaining in the Applicability of the LCO is acceptable because the plant risk in MODE 3 is similar to or lower than the risk in MODE 4 (Ref. 5), because the time spent in MODE 3 to perform the necessary repairs to restore the system to OPERABLE status will be short.
However, voluntary entry into MODE 4 may be made as it is also an acceptable low-risk state.
Required Action D.1 is modified by a Note that states that LCO 3.0.4.a is not applicable when entering MODE 3. This Note prohibits the use of LCO 3.0.4.a to enter MODE 3 during startup with the LCO not met.
However, there is no restriction on the use of LCO 3.0.4.b, if applicable, because LCO 3.0.4.b requires performance of a risk assessment addressing inoperable systems and components, consideration of the results, determination of the acceptability of entering MODE 3, and establishment of risk management actions, if appropriate. LCO 3.0.4 is not applicable to, and the Note does not preclude, changes in MODES or other specified conditions in the Applicability that are required to comply with ACTIONS or that are part of a shutdown of the unit.
The allowed Completion Time is reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.
E.1 and E.2 Movement of recently irradiated fuel assemblies in the secondary containment and CORE ALTERATIONS can be postulated to cause (continued)
HATCH UNIT 2 B 3.6-87 REVISION ++7
Secondary Containment B 3.6.4.1 BASES ACTIONS E.1 and E.2 (continued) significant fission product release to the secondary containment. In such .£..Cases, the secondary containment is the only barrier to release of fission products to the environment. CORE ALTERATIONS and Therefore, movement of recently irradiated fuel assemblies must be immediately suspended if the secondary containment is inoperable.
Suspension of tResethis aotivitiosactivity shall not preclude completing an action that involves moving a component to a safe position.
Required Action E.1 has been modified by a Note stating that LCO 3.0.3 is not applicable. If moving recently irradiated fuel assemblies while in MODE 4 or 5, LCO 3.0.3 would not specify any action. If moving recently irradiated fuel assemblies while in MODE 1, 2, or 3, the fuel movement is independent of reactor operations.
Therefore, in either case, inability to suspend movement of recently irradiated fuel assemblies would not be a sufficient reason to require a reactor shutdown.
SURVEILLANCE SR 3.6.4.1.1 REQUIREMENTS Verifying that secondary containment equipment hatches are closed ensures that the infiltration of outside air of such a magnitude as to prevent maintaining the desired negative pressure does not occur and provides adequate assurance that exfiltration from the secondary containment will not occur. SR 3.6.4.1.1 also requires equipment hatches to be sealed. In this application, the term "sealed" has no connotation of leak tightness. When the secondary containment configuration excludes Zone I and/or Zone II, this SR also includes verifying the hatches and doors separating the common refueling floor zone from the reactor building(s). The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
SR 3.6.4.1.2 Verifying that one secondary containment access door in each access opening is closed provides adequate assurance that exfiltration from the secondary containment will not occur. An access opening contains one inner and one outer door. The intent is to not breach the secondary containment, which is achieved by maintaining the inner or outer portion of the barrier closed except when the access opening is being used for entry and exit. The phrase "being used for entry and exit ensures the time both doors may be open simultaneously is limited to the time it takes to traverse through a door, which is insignificant. When the secondary containment configuration excludes Zone I and/or Zone II, this SR also includes verifying the doors separating the common refueling floor zone from the reactor building(s).
(continued)
HATCH UNIT 2 B 3.6-88 REVISION ++7