ML23341A137
| ML23341A137 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  (NPF-057) |
| Issue date: | 01/16/2024 |
| From: | James Kim NRC/NRR/DORL/LPL1 |
| To: | Mcfeaters C Public Service Enterprise Group |
| References | |
| EPID L-2023-LLA-0054 | |
| Download: ML23341A137 (1) | |
Text
January 16, 2024 Charles V. McFeaters President and Chief Nuclear Officer PSEG Nuclear LLC - N09 P.O. Box 236 Hancocks Bridge, NJ 08038
SUBJECT:
HOPE CREEK GENERATING STATION - ISSUANCE OF AMENDMENT NO. 235 RE: REVISE TRIP AND STANDBY AUTO-START LOGIC ASSOCIATED WITH SAFETY RELATED HEATING, VENTILATION AND AIR CONDITIONING (EPID L-2023-LLA-0054)
Dear Charles McFeaters:
The U.S. Nuclear Regulatory Commission (NRC, the Commission) has issued the enclosed Amendment No. 235 to Renewed Facility Operating License No. NPF-57 for the Hope Creek Generating Station (Hope Creek). The amendment consists of changes to the Hope Creek Updated Final Safety Analysis Report (UFSAR) in response to your application dated April 18, 2023.
The amendment modified the operation of safety related heating, ventilation, and air conditioning (HVAC) trains as described in the UFSAR for Hope Creek. The proposed change modified a portion of the trip and standby start logic for the safety related HVAC trains from an automatic function to a manual operator action.
C. McFeaters A copy of the related safety evaluation is also enclosed. A Notice of Issuance will be included in the Commissions monthly Federal Register notice.
Sincerely, James S. Kim, Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-354
Enclosures:
- 1. Amendment No. 235 to Renewed License No. NPF-57
- 2. Safety Evaluation cc: Listserv
/RA/
PSEG NUCLEAR LLC DOCKET NO. 50-354 HOPE CREEK GENERATING STATION AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 235 Renewed License No. NPF-57 1.
The U.S. Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment filed by PSEG Nuclear LLC dated April 18, 2023, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commissions rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commissions regulations set forth in 10 CFR Chapter I; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commissions regulations and all applicable requirements have been satisfied.
2.
Accordingly, by Amendment No. 235, Renewed Facility Operating License No. NPF-57 is hereby amended to authorize the change to the Updated Final Safety Analysis Report (UFSAR) as requested by letter dated April 18, 2023, and evaluated in the NRC staffs safety evaluation enclosed with this amendment.
3.
This license amendment is effective as of its date of issuance and shall be implemented within one year from the date of issuance. The licensee shall submit the update of the UFSAR authorized by this amendment in accordance with 10 CFR 50.71(e).
FOR THE NUCLEAR REGULATORY COMMISSION Hipólito J. González, Chief Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Date of Issuance: January 16, 2024 Hipolito J.
Gonzalez Digitally signed by Hipolito J. Gonzalez Date: 2024.01.16 13:53:51 -05'00' SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 235 TO RENEWED FACILITY OPERATING LICENSE NO. NPF-57 PSEG NUCLEAR LLC HOPE CREEK GENERATING STATION DOCKET NO. 50-354
1.0 INTRODUCTION
By letter dated April 18, 2023, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23108A035), PSEG Nuclear LLC (PSEG, the licensee) requested changes to Section 9, Auxiliary Systems, of the Updated Final Safety Analysis Report (UFSAR) for the Hope Creek Generating Station (Hope Creek).
Specifically, the proposed changes would modify the automatic actuation logic for the Control Room Supply (CRS), Control Equipment Room Supply (CERS), and Reactor Building Equipment Area Cooling (RBEAC) Heating, Ventilation and Air Conditioning (HVAC) systems.
2.0 REGULATORY EVALUATION
2.1
System Description
2.1.1 Control Room Supply System The CRS System maintains climate conditions within design limits in the main control room (MCR) and associated adjacent rooms. The CRS System is comprised of two 100 percent capacity air handling units. Each unit is supplied by a separate Class 1E emergency diesel generator-backed power source. Each air handler unit is comprised of an outside air intake, outside air radiation monitors, an outside air smoke detector, motorized isolation dampers, air filters, humidifier, chilled water coil, electric heating coil, and supply fan.
Air is produced to fulfill ventilation, exhaust, and pressurization requirements. Each air handler unit is connected to a common Seismic Category I supply and return duct system that distributes supply air throughout the rooms. Air is returned to the rooms by a control room return air (CRRA) fan to the CRS unit. Supply air temperature of the CRS unit is controlled by a temperature controller modulating the electric heating coil or chilled water valve.
The CRRA fan operates in conjunction with the CRS fan; therefore, positive pressure is maintained in the duct to the CRS fan. Filter differential pressures and airflow for each CRS unit are indicated in the MCR. Upon receiving a loss-of-coolant accident (LOCA) or high radiation signal, isolation dampers automatically close and divert fresh air to the Control Room Emergency Filtration (CREF) system. Following isolation, the CREF unit is started automatically to maintain pressure, inhibit air leakage into the MCR, and provide filtration to maintain post-accident MCR habitability.
The chilled water for the cooling coils in each unit is supplied by a Seismic Category I, independent Chilled Water Supply System. The chilled water supply system is interlocked with the CRS supply air fan so that the water chiller cannot operate without an energized supply fan.
Failure of an operating supply fan is annunciated in the MCR and trips its associated chilled water circulating pump. The trip of the chilled water circulating pump causes a trip of the associated chiller which automatically starts the standby chilled water and air systems.
2.1.2 CERS System The CERS system is a safety-related system that provides ventilation, cooling, and heating to the diesel area HVAC equipment room and all elevations within the control area of the Auxiliary Building except the MCR. These areas include the control area HVAC room, electrical access inverter area, control equipment room and mezzanine, cable spreading room, battery rooms, and electrical equipment room. The CERS consists of two 100 percent capacity air handling units, each supplied by a separate Class 1E power source. Each CERS unit includes a fan, chilled water coils, an electric heating coil, and high efficiency air filters. The CERS operates during normal, shutdown, and abnormal plant operation. It is automatically connected to the emergency diesel generator associated with its division in event of a loss of offsite power (LOOP).
The chilled water cooling coils in each CERS unit are supplied by the same Seismic Category I chilled water system that serves the CRS system. Like the CRS, the chilled water system is interlocked with the supply air fan so that the water chiller cannot operate without the fan being energized. Also like the CRS, failure of the operating supply fan is annunciated in the MCR and trips the in-service train of chilled water. Both standby trains of chilled water supply and air systems are then automatically started.
2.1.3 RBEAC System The RBEAC system is a subsystem to the Reactor Building HVAC system which provides cooling to Engineered Safety Function (ESF) equipment areas and the Safety Auxiliaries Cooling System (SACS) pump rooms. Redundant cooling and air handler trains exist for each area. Cooling supplied to the unit coolers for the SACS pump rooms is supplied by the control area chilled water system. The unit coolers for the ESF areas and SACS are actuated automatically when room temperatures increase to its predetermined setpoint. If the lead cooler train fails to maintain the room temperature, the standby cooler train starts automatically at a predetermined temperature setpoint.
Each SACS pump room is provided with redundant trains of chillers with two supply fans per Train. Each pair of unit coolers serving the SACS pump rooms is set up in a lead-lag mode.
The auto-lead cooler train automatically starts when the area temperature exceeds the setpoint.
If the auto-lead fan fails, the associated control area chilled water circulating pump stops and the standby control area chilled water circulating pump starts which auto-starts the standby cooler train. The temperature in each SACS pump room is indicated in the MCR.
2.1.4 Control Area Chilled Water System The Control Area Chilled Water System consists of two subsystems: the Control Room Chilled Water System and the Safety-Related Panel Room Chilled Water System. These subsystems provide chilled water which maintains ambient air temperatures for different portions of the Auxiliary Building within required limits of the structures systems and components in these areas. Both subsystems have two independent 100 percent capacity chilled water loops which each include a centrifugal water chiller, a chilled water circulating pump, a head tank, a demineralizer, and various air-cooling coils in the areas served. Cooling water for the chiller condensers is provided by the SACS. One chilled water loop in each subsystem operates while the other is on standby. Each operating chiller is powered from the same Class 1E bus as the chilled water pump and the air-cooling units in the loops. A MCR alarm is initiated upon low chilled water flow or high or low chilled water supply temperature in the operating loop. The operating loop automatically shuts down and the standby loop is automatically energized when these conditions are detected. Upon receipt of a LOCA signal, the standby chilled water train automatically starts and runs in parallel with the operating train until the operator manually secures one train.
2.1.5 Ventilation Supply Fan Assignments The supply fans affected by the proposed change provide forced ventilation to the following plant areas:
The 1A(B)VH403 fans service the MCR, Shift Supervisors Office and Control Room Computer room.
The 1A(B)VH407 fans service the following areas:
o HVAC Equipment Rooms 5703, 5602, and 5630; o
Cable Spreading rooms 5403 and 5202; o
Inverter Rooms 5447 and 5448; o
Equipment Rooms 5402, 5102, 5103, 5105, and 5129; o
Battery Rooms 5128, 5104 and 5126; and o
Various corridors and stairwells.
The 1A(B/C/D)VH214 fans service the A and B SACS pump rooms.
2.2 Description of Changes The license amendment request (LAR) does not involve any change of the technical specifications (TS). The LAR proposes changes to the UFSAR which do not impact the TS. This change modifies the current HVAC trip and auto-start logic. The current CRS, CERS, and RBEAC HVAC systems all have an automated trip function where a trip of any of these ventilation systems or the components that allow them to function properly induces a shutdown of the running unit and an automatic start of the standby redundant HVAC unit. The auto-start logic will be modified to only occur in the event of a LOCA or LOOP to preserve MCR habitability.
2.3 Applicable Regulatory Requirements Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix A, General Design Criteria for Nuclear Power Plants, establishes minimum requirements for the principal design criteria for boiling water-cooled nuclear power plants similar in design and location to plants for which construction permits have been issued by the U.S. Nuclear Regulatory Commission (NRC, the Commission). The General Design Criteria (GDC) are typically applicable to other types of nuclear power units and are intended to provide guidance in establishing the principal design criteria for similar units.
GDC 13, Instrumentation and control, states:
Instrumentation shall be provided to monitor variables and systems over their anticipated ranges for normal operation, for anticipated operational occurrences, and for accident conditions as appropriate to assure adequate safety, including those variables and systems that can affect the fission process, the integrity of the reactor core, the reactor coolant pressure boundary, and the containment and its associated systems. Appropriate controls shall be provided to maintain these variables and systems within prescribed operating ranges.
GDC 19, Control Room, states:
A control room shall be provided from which actions can be taken to operate the nuclear power unit safely under normal conditions and to maintain it in a safe condition under accident conditions, including loss-of-coolant accidents.
Adequate radiation protection shall be provided to permit access and occupancy of the control room under accident conditions without personnel receiving radiation exposures in excess of 5 rem whole body, or its equivalent to any part of the body, for the duration of the accident. Equipment at appropriate locations outside the control room shall be provided (1) with a design capability for prompt hot shutdown of the reactor, including necessary instrumentation and controls to maintain the unit in a safe condition during hot shutdown, and (2) with a potential capability for subsequent cold shutdown of the reactor through the use of suitable procedures.
GDC 23, Protection system failure modes, states:
The protection system shall be designed to fail into a safe state or into a state demonstrated to be acceptable on some other defined basis if conditions such as disconnection of the system, loss of energy (e.g., electric power, instrument air),
or postulated adverse environments (e.g., extreme heat or cold, fire, pressure, steam, water, and radiation) are experienced.
GDC 44, Cooling Water, states:
A system to transfer heat from structures, systems, and components important to safety, to an ultimate heat sink shall be provided. The system safety function shall be to transfer the combined heat load of these structures, systems, and components under normal operating and accident conditions.
The requirements described in TS 3/4.7.2, Control Room Systems, ensures that a redundant CREF system is always on standby. This amendment does not impact acceptable operating conditions of the reactor nor change the TS.
3.0 TECHNICAL EVALUATION
3.1 Technical Discussion The licensee states that a trip of any of the fans listed in Section 2.1.5 of this evaluation currently causes a trip of the 1A(B)VH403 fan that services the MCR which results in entry into a seven-day action per TS 3.7.2.1 for loss of one CREF system. The licensee further states that this seven-day action presents an unnecessary challenge to operations and maintenance personnel in troubleshooting and restoring the affected train. In addition, since the trip is received simultaneously across all fans, the chilled water pump and the chiller upon trip of any of the operating supply fans, the trip sequence impedes the ability to ascertain and troubleshoot the cause of the initial supply fan failure.
The licensee asserts that the removal of the trip and auto-start function of the standby chiller/fan train upon failure of any one supply fan allows time to identify the initial fan failure and that this additional time also allows plant staff to troubleshoot and potentially correct the condition (e.g., reset of a thermal overload on a breaker) and maintain the in-service chiller/ventilation train or place the standby train into service.
The CRS and CERS systems are support systems and are not directly associated with shutting down the reactor, maintaining core cooling or maintaining primary containment. However, since the CRS, CERS, and RBEAC systems provide a safety related support function, they are designed with fully redundant trains of chillers, chilled water circulating pumps and supply fans with auto-start features as a way of providing a single failure proof means to cool plant areas containing accident mitigating structures, systems, and components (SSCs).
The licensees proposal replaces the auto trip and start logic of the standby chiller/ventilation train with a manual operator action upon failure of any one of the operating supply fans and states this maintains a fully redundant ventilation/chiller train on standby. Automatic chiller/ventilation train trip and auto start logic will still be maintained for: (1) failure of either the chilled water circulating pump or the associated chiller, (2) a LOOP signal, and (3) a LOCA signal. Therefore, the licensee believes that the single failure proof design attributes of the CRS, CERS, and RBEAC systems during normal operations are still maintained though partially dependent on manual action.
In its amendment proposal, the licensee states that an immediate trip and auto-start of the standby ventilation/chiller train is not warranted on only the loss of a supply fan and that failure of one supply fan in the operating HVAC train does not defeat the heat removal capability of the remaining components in that train. While troubleshooting of a failed supply fan is taking place, the remaining operating chiller and fan units in the train are still providing cooling to their respective areas.
The licensee states that the immediate auto-starting of the standby ventilation train in response to a supply fan failure places undue transient wear on the components in the standby train which is often unnecessary. In the event the supply fan failure can be restored to service in a reasonable amount of time based on observed heat rise in the affected areas, the standby chiller/ventilation train would not need to be started, thus maintaining the full level of cooling system redundancy. Additionally, auto-starting the standby train due to a fan failure complicates the ability to effectively troubleshoot the fan condition(s) that caused the trip of the in-service train which resulted in the auto-start of the standby train.
The redundant train will still auto-start to maintain ambient conditions for the areas serviced by the CRS, CERS, and RBEAC systems if the in-service chiller or chill water circulating pump trips. Unavailability of a chiller and/or chilled water circulating pump will directly impact the heat removal capability of the entire ventilation train and auto transfer to the standby train is warranted to maintain room temperatures within limits and support the single failure criterion.
However, the licensee states that the trip of any one supply fan does not immediately impact the heat removal functions of the entire chiller/ventilation train.
In its amendment request, the licensee provided the following description of the potential heat rise in the affected areas:
Heat rise in the areas affected by a tripped supply fan has been conservatively shown to be gradual enough such that there is sufficient time to assess the affected fan unit and the cause of its trip and, if unable to immediately restore the fan, take manual action to place the standby ventilation/chiller train in service prior to exceeding administrative temperature limits of affected areas. The heat rise in response to a tripped fan is dependent on a number of factors such as the time of year, heat loads in service and overall chiller performance. Based on Generation of Thermal-Hydraulic Information for Containments (GOTHIC) calculations, the worst case area heat rise is associated with the trip of the 1A(B)VH407 CERS Supply fan. The GOTHIC temperature rise assessments are based on conservative assumptions for thermal inputs into the Control Equipment Room (e.g., maximum electrical loads are assumed to be operating).
Current abnormal operating procedures direct operators to monitor the temperature of impacted plant areas in response to a loss of forced ventilation in those areas. Based on observed area temperatures, these procedures direct actions to implement alternative cooling methods such as opening room doors and establishing alternative fan cooling. These alternative cooling methods are not credited in any of the GOTHIC calculations that modeled the fan trip scenarios.
The licensee believes the GOTHIC calculations indicate that sufficient time exists under worst case conditions to assess the cause for the CERS fan trip and perform the manual ventilation train swap prior to the control area exceeding administrative limits on room temperature. These administrative limits on room temperature are established for long term equipment reliability and are not limits associated with temperature induced failure of SSCs.
The action required by the operator to place the standby ventilation/chiller train in service is procedurally controlled and consists of depressing a single pushbutton in the MCR to trip the in-service chill water pump which will cause the standby train to auto-start. The licensee states that these operator actions for fan assessment and transferring cooling trains can be performed well before administrative temperature limits will be exceeded based on worst case GOTHIC modeling results.
The licensee states that there is another positive aspect to this logic change in that the elimination of the automatic trip and standby start function on a trip of a supply fan will simplify operator actions associated with Appendix R, Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979, response. Because both trains of chillers serve supply fans in the same SACS room, a fire in one of those rooms is assumed to trip both trains of chilled water due to assumed fire-induced trips of the supply fans. As a result, the licensee explains that an existing Appendix R manual action is required to open the affected fan breakers in the reactor building to allow the chillers to be placed back into service. Removing the fan trip input to the auto trip/standby start logic will negate the need for this action, thus simplifying operator actions in response to a fire in this area.
In its amendment request, the licensee described how the systems response to a LOOP (referred to as LOP by the licensee) and LOCA would not be affected by the request change by stating the following:
The designed response of the CRS, CERS and RBEAC systems to other analyzed events are not being impacted by this proposed change. Currently, in the event of a Loss of Offsite Power (LOP), the running chillers, pumps and supply fans servicing these systems will trip on undervoltage. The LOP sequencer, which automatically loads the emergency buses in response to a LOP, will provide start signals to both trains. The operator then takes manual action to secure one of the running trains. Similarly, upon a LOCA signal, the in-service ventilation train will continue running and the standby train will receive an auto-start signal from the LOCA load sequencer. The control room operator then manually secures one of the operating trains. In the unlikely event a LOCA were to occur while plant personnel were assessing a tripped supply fan prior to taking manual action to start the standby train, the standby train will automatically receive a start signal to ensure forced cooling of post-accident SSCs. Therefore, the single failure criterion for the CRS and CERS systems will still be maintained relative to servicing heat loads from post-accident SSCs following this proposed change.
Therefore, the licensee states that reliance on manual operator action to swap to the backup chiller/ventilation train in response to a supply fan trip is warranted and provides greater flexibility to operating and maintenance personnel to address unanticipated issues with supply fans.
3.2 NRC Staff Conclusion
The staff reviewed the proposed change which replaces an automatic action with a manual action to trip an in-service chiller/ventilation train servicing the CRS, CERS, and RBEAC systems and start the standby train in response to a failure of any supply fan within the operating train.
The staff recognizes that the CRS, CERS, and RBEAC systems are not initiators of any accident and do not directly mitigate any analyzed accident or transient and finds that sufficient time exists to take manual action to place the standby chiller/ventilation train into service prior to the temperature within the areas served by these systems to reach a level that would impact the operation or reliability of the equipment in those areas. The staff confirmed that all accident mitigating SSCs will remain capable of performing their design functions.
The proposed change does not alter any SSC analyzed in the safety analysis contained in Chapter 15 of the UFSAR, including instrument setpoints, nor does it change the assumptions contained in the safety analyses. The proposed change only affects the auto-trip and standby start logic associated with the CRS, CERS, and RBEAC ventilation trains which have no nexus to any analyzed margin of safety. All plant SSCs will continue to meet their design basis functional requirements as described in the UFSAR Chapter 15 safety analyses.
Additionally, the proposed logic change does not directly impact control of the reactor. To the extent that the CRS maintains operator ability to function and control the reactor, automated system logic is still in place in case of foreseen accidents such as LOCA or LOOP. Automated logic in these scenarios allows for total operational control of the accident situation and this ensures control room habitability and radiation protection while operators handle an emergency situation. The automated system logic is also still in place if an operating in-service chiller or chill water circulating pump trips.
The staff also reviewed the facilitys TS and finds that no TS changes are needed as a result of the logic modification/Chapter 9 of the UFSAR revision.
Based on this comprehensive review, the staff finds the proposed changes acceptable. The requirements of GDC 13, 19, 23, and 44 all continue to be met. Additionally, following its review of the facilitys TS the staff find the requirements of 10 CFR 50.36 will continue to be met.
Therefore, the staff finds the proposed modification of the ventilation system logic and the changes to Chapter 9 of the UFSAR acceptable.
4.0 STATE CONSULTATION
In accordance with the Commissions regulations, the New Jersey State official was notified of the proposed issuance of the amendment on January 5, 2024. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes requirements with respect to the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, as published in the Federal Register on June 13, 2023 (88 FR 38551), and there has been no public comment on such finding.
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) there is reasonable assurance that such activities will be conducted in compliance with the Commissions 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.
Principal Contributor: D. Scully, NRR Date: January 16, 2024
ML23341A137 NRR-058 OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DSS/SCPB/BC NAME JKim KEntz BWittick DATE 12/12/2023 12/8/2023 12/4/2023 OFFICE OGC - NLO NRR/DORL/LPL1/BC NRR/DORL/LPL1/PM NAME BVaisey HGonzález JKim DATE 1/4/2024 1/16/2024 1/16/2024