ML14191B190
| ML14191B190 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 07/10/2014 |
| From: | David Helker Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-08-001, Rev 2, TSTF-523 | |
| Download: ML14191B190 (80) | |
Text
R.
2 1 h Description and Assessment Page 1 of
41.0 DESCRIPTION
The proposed change revises or adds Surveillance Requirements to verify that the system locations susceptible to gas accumulation are sufficiently filled with water and to provide allowances which permit performance of the verification.
The changes are being made to address the concerns discussed in Generic Letter 2008
-01, "Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems." The proposed amendment is consistent with TSTF
-523, Revision 2, "Generic Letter 2008
-01, Managing Gas Accumulation." 2.0 ASSESSMEN T 2.1 Applicability of Published Safety Evaluation Exelon Generation Company, LLC (EGC) ha s reviewed the model s afety evaluation dated December 23 , 2013 as pa rt o f t he Fede ral R egister N otice o f Availability.
This r eview i ncluded a review of the N RC's evaluation, as w ell as t he information pr ovided i n TSTF-52 3 , Revision 2. As des cribed i n the s ubsequent paragraphs, E GC has c oncluded that t he justifications pr esented i n t he TSTF-52 3 , Revision 2 proposal and the m odel s afety ev aluation prepared by t he NRC ar e applicable to Peach Bottom A tomic P ower Station , Un its 2 and 3 (P BAPS) and justify t his amendment f or incorporation of t he c hanges t o t he plant Te chnical Specifications (T Ss). The model safety evaluation discusses the applicable regulatory requirements and guidance, including the 10 CFR 50, Appendix A, General Design Criteria (GDC).
PBAPS is not licensed to the 10 CFR 50, Appendix A, GDC applicable to this change. PBAPS's Updated Final Safety Analysis Report (UFSAR), Appendix H, "Conformance to AEC (NRC) Criteria
," provides an assessment against the draft GDC published in 1967. A review has determined that the plant
-specific requirements are sufficiently similar to the Appendix A GDC as related to the proposed change. Therefore, the proposed change is applicable to PBAPS. 2.2 Optional Changes and Variations EG C is no t p roposing an y significant variations or dev iations from the TS c hanges des cribed i n TSTF-523 , Re vision 2, o r the applicable parts o f the N RC's m odel s afety ev aluation dated December 23, 2013. EGC i s no ting th e following minor v ariations from t he TS changes de scribed i n TSTF-5 23 , Revision 2: TSTF-523 i s base d on the S tandard Technical Specification (STS).
PBAPS has adop t ed the STS. Inthe cases listed bel ow the STS Section number corresponds t o a different plant TS Section number.BWR/4 STS Section 3.4.8, "RHR Shutdown Cooling System
- Hot Shutdown," corresponds toPBAPS TS Section 3.4.7, "RHR Shutdown Cooling System
- Hot Shutdown."BWR/4 STS Section 3.4.9, "RHR Shutdown Cooling System
- Cold Shutdown," correspondsto PBAPS TS Section 3.4.8, "RHR Shutdown Cooling System - Cold Shutdown." BWR/4 STS S ection 3.9.8 , " RHR - High Water Level ," c orresponds to PBA PS TS 3.9.7, " RHR - High Water Level." BWR/4 STS S ection 3.9.9, " RHR - Low Water Le vel," c orresponds to PBAPS T S 3.9.8, " RHR - Low Water Lev el."
Description and Assessment Page 2 of 4PBAPS has included changes to the SR for TS 3.6.2.5, "Residual Heat Removal Drywell Spray." TheRHR Drywell Spray system was not included in the generic TSTF
-523, Revision 2 proposedchange s; however, the RHR Drywell Spray System is one of the RHR systems at PBAPS and,therefore, is applicable to the GL 2008
-01 and the associated changes to the TS. The PBAPSproposed RHR Drywell Spray SR 3.6.2.5.3 is modeled after other proposed RHR SRs (i.e., RHRSuppression Pool Cooling SR 3.6.2.3.3)
.TSTF-523, Revision 2, Section 3.1, "Revise or Add Surveillance Requirements," states:Some LCOs only require one train or loop of DHR/RHR/SDC to be Operable at a given time. The proposed SR for those TS state "Verify the required [system]
[loop/train/subsystem] locations-" In the ISTS, the term "required" means "required by the LCO." The word "required" is added as a convention to avoid confusion since SRs are not applicable to equipment that is not required to be Operable. Corresponding changes are made to the Bases.
PBAPS included the term "required" for the following SRs: TSs 3.4.7, 3.4.8, 3.9.7 and 3.9.8. The P BAPS LC O B ases discussion of w hat c onstitutes an OPERABLE R HR S ubsystem for TSs3.4.7, 3.4.8, 3.6.2.3, 3.6.2.4, 3.6.2.5, 3.9.7 and 3.9.8 includes requiring the "[High PressureServiceWater] H PSW System p ump capable o f providing cooling to t he heat exchanger andas sociatedpiping, [and] v alves[, i nstrumentation, and c ontrols] a r e OPERABLE." Th e HPSW s ystemcomponents hav e been determined to no t be required to be i n the sco pe of this surveillance due tooperating experience and the design o f the system.
Therefore, a note was included to t he revise d oradded SRs for TSs 3.4.7, 3.4.8, 3.6.2.3, 3.6.2.4, 3.6.2.5, 3.9.7 and 3.9.8 t o exclude HPSW piping,valves, and pumps.EGC has reviewed these changes and determined that they are administrative and do not affect the applicability of TSTF
-523 , Revision 2 to the PBAPS TS.
3.0 REGULATORY ANALYSIS
3.1 No Significant Hazards Consideration Determination Exelon Generation Company, LLC (EGC) requests adopti on of T STF-5 23, R ev ision 2, " Generic Let ter 2 008-0 1, M anaging Gas Accumulation," w hich is an approved change t o t he Standard T echnical Specifications (STS), into the Peach Bottom Atomic Power Station , Un it s 2 and 3 Technical Specifications (TS). The proposed chang e revises or adds Surv eillance Requirements to verify that the system locations susceptible to gas accumulati on are sufficiently filled with water and to provide allowances which permit performance o f the verification.
EGC has evaluated whether or not a significant hazards consideration is involved with the proposed amendments by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:
Description and Assessment Page 3 of 41.Does the proposed change involve a significant increase in the probability or consequences of anaccident previously evaluated?Response: No.The proposed change revises or adds Surveillance Requirements (SRs) that require verificationthat the Emergency Core Cooling System s, the Suppression Pool Cooling System, theSuppression Pool Spray System, the Drywell Spray System, the Shutdown Cooling System, andthe Reactor Core Isolation Cooling System are not rendered inoperable due to accumulated gasand to provide allowances which permit performance of the revised verification. Gasaccumulation in the subject systems is not an initiator of any accident previously evaluated.
As aresult, the probability of any accident previously evaluated is not significantly increased. Theproposed SRs ensure that the subject systems continue to be capable of performing theirassumed safety function and are not rendered inoperable due to gas accumulation. Thus, theconsequences of any accident previously evaluated are not significantly increased.Therefore, the proposed change does not involve a significant increase in the probability orconsequences of an accident previously evaluated.
2.Does the proposed change create the possibility of a new or different kind of accident from anyaccident previously evaluated?Response: No.The proposed change revises or adds SRs that require verification that the Emergency CoreCooling Systems, the Suppression Pool Cooling System, the Suppression Pool Spray System, the Drywell Spray System, the Shutdown Cooling System, and the Reactor Core Isolation CoolingSystem are not rendered inoperable due to accumulated gas and to provide allowances whichpermit performance of the revised verification. The proposed change does not involve a physicalalteration of the plant (i.e., no new or different type of equipment will be installed) or a change inthe methods governing normal plant operation.
In addition, the proposed change does notimpose any new or different requirements that could initiate an accident. The proposed changedoes not alter assumptions made in the safety analysis and is consistent with the safety analysisassumptions.Therefore, the proposed change does not create the possibility of a new or different kind ofaccident from any accident previously evaluated.3.Does the proposed change involve a significant reduction in a margin of safety?Response: No.The proposed change revises or adds SRs that require verification that the Emergency CoreCooling Systems, the Suppression Pool Cooling System, the Suppression Pool Spray System,the Drywell Spray System, the Shutdown Cooling System, and the Reactor Core Isolation CoolingSystem are not rendered inoperable due to accumulated gas and to provide allowances whichpermit performance of the revised verification.
The proposed change adds new requirements tomanage gas accumulation in order to ensure the subject systems are capable of performing theirassumed safety functions.
The proposed SRs are more comprehensive than the current SRs and Description and Assessment Page 4 of 4will ensure that the assumptions of the safety analysis are protected. The proposed change does not adversely affect any current plant safety margins or the reliability of the equipment assumed in the safety analysis. Therefore, there are no changes being made to any safety analysis assumptions, safety limits or limiting safety system settings that would adversely affect plant safety as a result of the proposed change.
Therefore, the proposed change does not involve a significant reduction in a margin of safety.
Based on the above, EGC concludes that the proposed change presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.
3.2 Conclusions
In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public. 4.0 ENVIRONMENTAL EVALUATION The proposed change would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or Surveillance Requirement. However, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed change.
Proposed Technical Specification Changes (Mark
-Up) REVISED TECHNICAL SPECIFICATIONS PAGES
RHR Drywell Spray 3.6.2.5 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.2.5.1 Verify each RHR drywell spray subsystem manual, power operated, and automatic valve in the flow path that is not locked, sealed, or otherwise secured in position is in the correct position or can be aligned to the correct position.
In accordance with the Surveillance Frequency Control Program. SR 3.6.2.5.2 Verify each drywell spray nozzle is unobstructed.
In accordance with the Surveillance Frequency Control Program.
PBAPS UNIT 2 3.6-30b Amendment No. 288
RHR Drywell Spray 3.6.2.5 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.6.2.5.1 Verify each RHR drywell spray subsystem manual, power operated, and automatic valve in the flow path that is not locked, sealed, or otherwise secured in position is in the correct position or can be aligned to the correct position.
In accordance with the Surveillance Frequency Control Program. SR 3.6.2.5.2 Verify each drywell spray nozzle is unobstructed.
In accordance with the Surveillance Frequency Control Program.
PBAPS UNIT 3 3.6-30b Amendment No. 291
Proposed Technical Specification Bases Changes (Mark
-Up) (For Information Only)
REVISED TECHNICAL SPECIFICATION BASES PAGES
ECCS-Operating B 3.5.1 BASES APPLICABLE This LCO helps to ensure that the following acceptance SAFETY ANALYSES criteria for the ECCS, established by 10 CFR 50.46 (Ref. 8),
(continued) will be met following a LOCA, assuming the worst case single active component failure in the ECCS:
a.Maximum fuel element cladding temperature is 2200°F;b.Maximum cladding oxidation is 0.17 times the total cladding thickness before oxidation;c.Maximum hydrogen generation from a zirconium water reaction is 0.01 times the hypothetical amount that would be generated if all of the metal in the cladding surrounding the fuel, excluding the cladding
surrounding the plenum volume, were to react;d.The core is maintained in a coolable geometry; and e.Adequate long term cooling capability is maintained.
The limiting single failures are discussed in References 7, 14, and 15. The remaining OPERABLE ECCS subsystems provide the capability to adequately cool the core and prevent
excessive fuel damage.
The ECCS satisfy Criterion 3 of the NRC Policy Statement.
LCO Each ECCS injection/spray subsystem and five ADS valves are required to be OPERABLE. The ECCS injection/spray
subsystems are defined as the two CS subsystems, the two
LPCI subsystems, and one HPCI System. The low pressure ECCS
injection/spray subsystems are defined as the two CS
subsystems and the two LPCI subsystems.
With less than the required number of ECCS subsystems OPERABLE, the potential exists that during a limiting design
basis LOCA concurrent with the worst case single failure, the limits specified in Reference 8 could be exceeded. All
ECCS subsystems must therefore be OPERABLE to satisfy the
single failure criterion required by Reference 8.
As noted, LPCI subsystems may be considered OPERABLE during alignment and operation for decay heat removal when below the
actual RHR shutdown cooling isolation pressure in MODE 3, if
capable of being manually realigned (remote or local) to the (continued)
PBAPS UNIT 2 B 3.5-5 Revision No. 101 ECCS-Operating B 3.5.1 BASES APPLICABLE This LCO helps to ensure that the following acceptance SAFETY ANALYSES criteria for the ECCS, established by 10 CFR 50.46 (Ref. 8),
(continued) will be met following a LOCA, assuming the worst case single active component failure in the ECCS:
a.Maximum fuel element cladding temperature is 2200°F;b.Maximum cladding oxidation is 0.17 times the total cladding thickness before oxidation;c.Maximum hydrogen generation from a zirconium water reaction is 0.01 times the hypothetical amount that would be generated if all of the metal in the cladding surrounding the fuel, excluding the cladding
surrounding the plenum volume, were to react;d.The core is maintained in a coolable geometry; and e.Adequate long term cooling capability is maintained.
The limiting single failures are discussed in References 7, 14, and 15. The remaining OPERABLE ECCS subsystems provide the capability to adequately cool the core and prevent
excessive fuel damage.
The ECCS satisfy Criterion 3 of the NRC Policy Statement.
LCO Each ECCS injection/spray subsystem and five ADS valves are required to be OPERABLE. The ECCS injection/spray
subsystems are defined as the two CS subsystems, the two
LPCI subsystems, and one HPCI System. The low pressure ECCS
injection/spray subsystems are defined as the two CS
subsystems and the two LPCI subsystems.
With less than the required number of ECCS subsystems OPERABLE, the potential exists that during a limiting design
basis LOCA concurrent with the worst case single failure, the limits specified in Reference 8 could be exceeded. All
ECCS subsystems must therefore be OPERABLE to satisfy the
single failure criterion required by Reference 8.
As noted, LPCI subsystems may be considered OPERABLE during alignment and operation for decay heat removal when below the
actual RHR shutdown cooling isolation pressure in MODE 3, if
capable of being manually realigned (remote or local) to the (continued)
PBAPS UNIT 3 B 3.5-5 Revision No. 101
RHR Drywell Spray B 3.6.2.5 BASES (continued) APPLICABLE Reference 2 contains the results of analyses used to SAFETY ANALYSES predict primary containment pressure and temperature response following a spectrum of small steam line break sizes. Steam line breaks are the most limiting events for drywell temperature response, since steam has higher energy content than liquid. These analyses, with primary focus on the drywell temperature response, take credit for containment sprays and structural heat sinks in the drywell and the suppression pool airspace. These analyses demonstrate that, with credit for containment spray (drywell and suppression pool), drywell temperature is maintained within limits for Environmental Qualification (EQ) of equipment located in the drywell for the analyzed spectrum of small steam line breaks. The RHR Drywell Spray System satisfies Criterion 3 of the NRC Policy Statement.
LCO In the event of a small steam line break in the drywell, a minimum of one RHR drywell spray subsystem is credited in design analyses to mitigate the rise in drywell temperature and pressure caused by the steam line break, and to maintain the primary containment peak temperature and pressure below the design limits (Ref. 2). To ensure that these requirements are met, two RHR drywell spray subsystems (one in each loop) must be OPERABLE with power from two safety related independent power supplies. (The two subsystems must be in separate loops since the drywell spray sparger line valves are common to both subsystems in a loop.) Therefore, in the event of an accident, at least one subsystem is OPERABLE assuming the worst case single active failure. An RHR drywell spray subsystem is OPERABLE when one of the pumps, the associated heat exchanger, a HPSW System pump capable of providing cooling to the heat exchanger and associated piping, valves, instrumentation, and controls are OPERABLE. APPLICABILITY In MODES 1, 2, and 3, a steam line break in the drywell could cause a rise in primary containment temperature and pressure. In MODES 4 and 5, the probability and consequences of steam line breaks are reduced due to the pressure and temperature limitations in these MODES.
Therefore, maintaining RHR drywell spray subsystems OPERABLE is not required in MODE 4 or 5. (continued)
PBAPS UNIT 2 B 3.6-63b Revision No. 106 RHR Drywell Spray B 3.6.2.5 BASES (continued) APPLICABLE Reference 2 contains the results of analyses used to SAFETY ANALYSES predict primary containment pressure and temperature response following a spectrum of small steam line break sizes. Steam line breaks are the most limiting events for drywell temperature response, since steam has higher energy content than liquid. These analyses, with primary focus on the drywell temperature response, take credit for containment sprays and structural heat sinks in the drywell and the suppression pool airspace. These analyses demonstrate that, with credit for containment spray (drywell and suppression pool), drywell temperature is maintained within limits for Environmental Qualification (EQ) of equipment located in the drywell for the analyzed spectrum of small steam line breaks. The RHR Drywell Spray System satisfies Criterion 3 of the NRC Policy Statement.
LCO In the event of a small steam line break in the drywell, a minimum of one RHR drywell spray subsystem is credited in design analyses to mitigate the rise in drywell temperature and pressure caused by the steam line break, and to maintain the primary containment peak temperature and pressure below the design limits (Ref. 2). To ensure that these requirements are met, two RHR drywell spray subsystems (one in each loop) must be OPERABLE with power from two safety related independent power supplies. (The two subsystems must be in separate loops since the drywell spray sparger line valves are common to both subsystems in a loop.) Therefore, in the event of an accident, at least one subsystem is OPERABLE assuming the worst case single active failure. An RHR drywell spray subsystem is OPERABLE when one of the pumps, the associated heat exchanger, a HPSW System pump capable of providing cooling to the heat exchanger and associated piping, valves, instrumentation, and controls are OPERABLE. APPLICABILITY In MODES 1, 2, and 3, a steam line break in the drywell could cause a rise in primary containment temperature and pressure. In MODES 4 and 5, the probability and consequences of steam line breaks are reduced due to the pressure and temperature limitations in these MODES.
Therefore, maintaining RHR drywell spray subsystems OPERABLE is not required in MODE 4 or 5. (continued)
PBAPS UNIT 3 B 3.6-63b Revision No. 106 RHR Drywell Spray B 3.6.2.5 BASES (continued) SURVEILLANCE SR 3.6.2.5.1 REQUIREMENTS Verifying the correct alignment for manual, power operated, and automatic valves in the RHR drywell spray mode flow path provides assurance that the proper flow paths will exist for system operation. This SR does not apply to valves that are locked, sealed, or otherwise secured in position since these valves were verified to be in the correct position prior to locking, sealing, or securing. A valve is also allowed to be in the nonaccident position provided it can be aligned to the accident position within the time assumed in the accident analysis. This is acceptable since the RHR drywell mode is manually initiated. This SR does not require any testing or valve manipulation; rather, it involves verification that those valves capable of being mispositioned are in the correct position. This SR does not apply to valves that cannot be inadvertently misaligned, such as check valves.
The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
SR 3.6.2.5.2 This Surveillance is performed to verify that the spray nozzles are not obstructed and that flow will be provided when required. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. REFERENCES 1.UFSAR, Sections 5.2 and 14.6.3.2.GE-NE-0000-0011-4483, Project Task Report, Peach Bottom Atomic Power Station, Units 2 and 3, SIL 636 Evaluation.
PBAPS UNIT 2 B 3.6-63d Revision No. 106 RHR Drywell Spray B 3.6.2.5 BASES (continued) SURVEILLANCE SR 3.6.2.5.1 REQUIREMENTS Verifying the correct alignment for manual, power operated, and automatic valves in the RHR drywell spray mode flow path provides assurance that the proper flow paths will exist for system operation. This SR does not apply to valves that are locked, sealed, or otherwise secured in position since these valves were verified to be in the correct position prior to locking, sealing, or securing. A valve is also allowed to be in the nonaccident position provided it can be aligned to the accident position within the time assumed in the accident analysis. This is acceptable since the RHR drywell mode is manually initiated. This SR does not require any testing or valve manipulation; rather, it involves verification that those valves capable of being mispositioned are in the correct position. This SR does not apply to valves that cannot be inadvertently misaligned, such as check valves.
The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
SR 3.6.2.5.2 This Surveillance is performed to verify that the spray nozzles are not obstructed and that flow will be provided when required. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. REFERENCES 1.UFSAR, Sections 5.2 and 14.6.3.2.GE-NE-0000-0011-4483, Project Task Report, Peach Bottom Atomic Power Station, Units 2 and 3, SIL 636 Evaluation.
PBAPS UNIT 3 B 3.6-63d Revision No. 106