ML24026A301
| ML24026A301 | |
| Person / Time | |
|---|---|
| Site: | 05000611, 05000612 |
| Issue date: | 01/26/2024 |
| From: | Kairos Power |
| To: | Document Control Desk |
| Shared Package | |
| ML24026A299 | List: |
| References | |
| KP-NRC-2401-008 | |
| Download: ML24026A301 (1) | |
Text
KP-NRC-2401-008 Enclosure 1 Changes to Hermes 2 PSAR Chapter 7 (Non-Proprietary)
Preliminary Safety Analysis Report Instrumentation and Controls Figure 7.11: Instrumentation and Controls System Architect Kairos Power Hermes 2, Units 1 and 2 73 Revision 0
Preliminary Safety Analysis Report Instrumentation and Controls Kairos Power Hermes 2, Units 1 and 2 74 Revision 0
Preliminary Safety Analysis Report Instrumentation and Controls 7.2.1.1 Reactor Control System The RCS controls and monitors systems and components that support normal operation, planned transients, and normal shutdown of the reactor. The RCS controls the systems listed in Figure 7.11 and supports the following capabilities:
Reactivity control and planned transients/adjustments in power level Monitoring of core neutronics Pebble handling and storage Monitoring and control of temperature in the reactor The RCS controls reactivity for normal operations and normal shutdown using reactor control elements and reactor shutdown elements in the reactivity control and shutdown system (RCSS) (see Section 4.2).
The RCS is capable of incrementally changing the position of reactor control elements and of releasing the control and shutdown elements. The RCS is only capable of withdrawing elements one at a time and the RCS includes a limit on the rate at which a control element can be withdrawn, as also discussed in Section 4.2.2. In this way the design precludes, with margin, the potential for prompt criticality and rapid reactivity insertions. The RCS inputs include reactor outlet temperature and reactor inlet temperature sensors and source and power range neutron excore detectors. The RCS also provides a reactor monitoring function to monitor plant components that are associated with reactor functions.
The RCS uses source and power range sensors that are located outside the reactor vessel for reactor control.
The RCS controls pebble insertion and extraction, invessel pebble handling, and exvessel pebble handling in the pebble handling and storage system (PHSS) (see Section 9.3). The RCS is capable of counting linearized pebbles external to the vessel, controlling the rate of pebble insertion and removal from the vessel, and controlling pebble distribution within the PHSS.
The RCS controls the reactor thermal management system (RTMS) (see Section 9.1.5) to monitor the temperature of the primary system to maintain it within the normal operating envelope and to implement planned transients. The RCS controls external heating elements in the RTMS to prevent overcooling.
The RCS provides the capability for event monitoring and active actuation of the decay heat removal system (DHRS) (See Section 6.3.1).
7.2.1.2 Reactor Coolant Auxiliary Control System The RCACS controls and monitors systems and components that support normal operation in the core.
The system supports the following capabilities in the core:
Chemistry control in the primary system Highlighted text was previously changed.
Inventory management system control Submitted on 1324 (ML24003A766).
Inert gas system control in the primary loops Tritium management system monitoring and control Remote handling maintenance and inspection system monitoring and control The RCACS controls the chemistry control system (see Section 9.1.1) to monitor reactor coolant chemistry. The monitoring systems provide information to facilitate maintaining coolant purity and circulating activity within specifications for the system.
Kairos Power Hermes 2, Units 1 and 2 77 Revision 0
Preliminary Safety Analysis Report Instrumentation and Controls The chilled water system, as discussed in Section 9.7.4, is controlled and monitored to supply cooling water to nonsafety related SSCs.
The electrical supply, as discussed in Chapter 8, is controlled and monitored to support the nonsafety related normal and backup power supply.
The RBHAVAC is controlled and monitored to supply reactor building HVAC, as discussed in Section 9.2.
The environmental monitoring system, as discussed in Section 11.1.7, monitors radiation levels in Highlighted text was unrestricted areas and radioactive material in effluents. previously changed.
Submitted on 1324 7.2.2 Design Bases (ML24003A766).
Consistent with Principal Design Criteria (PDC) 13, the PCS is designed to monitor variables and systems over their anticipated ranges for normal operation, and over the range defined in postulated events.
7.2.3 System Evaluation The PCS is designed to monitor plant and unit parameters and maintain systems within normal operating range. The PCS is also designed to control planned transients associated with anticipated operational occurrences and maintain the affected reactor in a shutdown state. These functions are consistent with PDC 13. The PCS does not perform a safetyrelated function. Finally, the PCS is designed so that it cannot interfere with the RPSs ability to perform its safety functions; see Section 7.3 for more information about the isolation of the RPS from the PCS.
The PCS is a digital system that controls the reactor power about a point set by the operator. The control system uses linear average temperature and flow rate in the primary system as variable inputs to control power level so that it remains within the normal operating envelope. The PCS controls electrical power generation about a point set by the operators using steam flow rates, feedwater flow rates, and feedwater temperatures as inputs to control the positions of turbine control valves, turbine bypass valves, and feedwater regulating valves to balance the turbine load from each unit. The system design meets the applicable portions International Electrotechnical Commission (IEC) standard 61131 for industrial controllers (Reference 1), and the applicable portions of the cyber security standard IEC 62443 (Reference 2). Table 7.22 lists other standards applied to the PCS. Applicable portions of IEEE 1012 2017 (Reference 3) are used for verification and validation of PCS components, which is consistent with the nonsafety related classification of the PCS.
Action in the PCS is designed to accurately and reliably provide control signal for all modes of normal operation. The PCS is also designed to provide timely control signals, with further analysis of timeliness to be provided in an application for the Operating License.
The PCS includes interlocks and inhibits that prohibit or restrict operation of the reactor, PHSS, and the power generation system unless certain operating conditions are met. The following interlocks are included in the control system design:
An interlock that prohibits reactivity control element withdrawal until there is sufficient neutron count rate to ensure that nuclear instruments are responding to neutrons.
Interlocks are also provided related to startup power level and pebble handling as detailed in Table 7.23.
An interlock that prevents the opening of a units main steam isolation valve following a reactor trip until there is sufficient steam production to ensure that a turbine imbalance will not occur.
Kairos Power Hermes 2, Units 1 and 2 710 Revision 0