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Kairos Power LLC, Presentation Slides for the April 4, 2023 ACRS Kairos Power Subcommittee Meeting
	ML23088A069
Person / Time
Site:	Hermes File:Kairos Power icon.png
Issue date:	03/28/2023
From:	; Kairos Power
To:	; Office of Nuclear Reactor Regulation
Shared Package
ML23088A067	List: ML23088A068; ML23088A069;
References
	KP-NRC-2303-004
	Download: ML23088A069 (1)
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KP-NRC-2303-004 Enclosure 1 Presentation Slides for the April 4, 2023 ACRS Kairos Power Subcommittee Meeting (Non-Proprietary)

Hermes PSAR Chapter 5 Heat Transport System N I CO LA S Z W E I BA UM - DI RE CTO R, S A LT S Y S T E MS DE S I G N A CRS K A I RO S P O W E R SU BCO M MI TT E E M E E T I NG A P RI L 4 , 2 0 2 3 Copyright © 2023 Kairos Power LLC. All Rights Reserved.

1 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

5.1 Primary Heat Transport System: Description

The PHTS is responsible for transporting heat from the reactor to the ultimate heat sink (environmental air) during power operation and during normal shutdown

The PHTS operates near atmospheric pressure and does not provide a safety-related heat removal function No driving force for energetic releases during a pipe break

The PHTS is a non-safety-related system Parameter Value Thermal duty 35 MWth Number of HRRs 1 Number of hot legs 1 Number of cold legs 2 Primary loop line size 8-12 in nominal pipe size HRR inlet coolant temperature 600-650oC HRR outlet coolant temperature 550o C Nominal flow rate 210 kg/s PHTS design pressure 525 kPa(g)

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5.1 Primary Heat Transport System: Description (cont.)

Primary Loop Piping Transports reactor coolant between Reactor Vessel and Heat Rejection Radiator Not a safety-related portion of the reactor coolant boundary

Primary Salt Pump (PSP)

Variable speed, cartridge style pump located on the Reactor Vessel head Inlet extends downwards through the Reactor Coolant free surface Hot leg anti-siphon function performed by geometric features of the PSPs downward-facing inlet No safety-related function for the PSP but safety-related trip to maintain Reactor Coolant inventory level

Heat Rejection Subsystem (HRS)

Provides for heat transfer from the Reactor Coolant to the ultimate heat sink (environmental air)

Consists of a Heat Rejection Radiator, Heat Rejection Blower, and associated ducting and thermal management No safety-related function for the HRS but safety-related blower trip upon tube failure minimizes forced air ingress

Primary Loop Thermal Management Provides non-nuclear heating and insulation to the PHTS as needed for various operations No safety-related function Copyright © 2023 Kairos Power LLC. All Rights Reserved.

3 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

5.1 Primary Heat Transport System: Reactor Coolant

Flibe (2LiF-BeF2) - Liquid Fluoride Salt Coolant

Negative temperature coefficient of reactivity

Secondary barrier to fission product release

Thermophysical properties Topical report approved by NRC, "Reactor Coolant for the Kairos Power Fluoride Salt-Cooled High Temperature Reactor" (KP-TR-005)

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5.1 Primary Heat Transport System: Design Basis

The PHTS SSCs that are a part of the reactor coolant boundary will be designed to ASME B31.3 and BPVC Section VIII codes and standards

Failure of the non-safety-related PHTS components during seismic events does not affect the performance of nearby safety-related SSCs (PDC 2)

Adequate coolant flow is maintained to assure SARRDLs will not be exceeded under any condition of normal operation (PDC 10)

The PHTS is designed with features that ensure power oscillations cannot result in conditions exceeding SARRDLs (PDC 12)

The reactor coolant provides control of the release of radioactive materials during normal operations and postulated events through the accumulation of radionuclides (PDCs 16, 60)

The PSP casing is designed with geometric features to prevent reactor coolant from being siphoned below the pump casing inlet elevation to maintain reactor coolant inventory in the event of a break in an external portion of the PHTS (PDC 33)

The PHTS is designed with features that support maintaining reactor coolant inventory and maintaining reactor coolant purity by limiting air ingress (PDCs 33, 70)

The PHTS will be designed according to 10 CFR 20.1406, to the extent practicable, to minimize contamination and support eventual decommissioning Copyright © 2023 Kairos Power LLC. All Rights Reserved.

5 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

Hermes PSAR Chapter 7 Instrumentation and Controls Systems A N T H O N IE CI LLI E RS - DI RE CTO R, I & C A N D E LE CT RI CA L A CRS K A I RO S P O W E R S U BCO M MI TT E E M E E T I N G A P RI L 4 , 2 0 2 3 Copyright © 2023 Kairos Power LLC. All Rights Reserved.

1 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

7.1 Instrumentation & Controls Systems: Overview The Instrumentation and Controls (I&C) Systems include:

The Reactor Protection System (RPS) is a safety-related system that provides protection for reactor operations by initiating signals to mitigate the consequences of postulated events and ensure safe shutdown.

The Plant Control System (PCS) is a non-safety related system responsible for controlling plant parameters during normal operations and providing data to the Main Control Room control consoles.

The Main Control Room (MCR) provides a means for operators to monitor the behavior of the plant and control performance of the plant. The Remote Onsite Shutdown Panel (ROSP) provides a separate means to shut down the plant and to monitor plant parameters in response to postulated event conditions.

Sensors are used to provide information about plant parameters as inputs to the PCS and RPS.

Sensors that provide input to the RPS are safety-related. The PCS receives inputs from non-safety-related sensors, as well as safety-related sensors through safety-related isolation device.

2 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

3 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

7.2 Plant Control System

The PCS implements its monitoring and control functions through a series of subsystems:

The Reactor Control System performs functions associated with reactivity control and power level adjustments, monitoring of core neutronics, pebble handling and storage, and monitoring and controlling temperature in the reactor.

The Reactor Coolant Auxiliary Control System performs functions associated with chemistry control, inventory management system control, inert gas system control, and tritium management system monitoring and control.

The Primary Heat Transport Control System performs functions associated with control of the flow rate through the Primary Heat Transport System (PHTS), PHTS thermal management, control of the heat rejection system, and primary loop draining, filling, and piping monitoring.

The PCS receives inputs from non-safety-related sensor inputs, as well as safety-related sensor inputs. The PCS is electronically and functionally isolated from the safety-related RPS using a safety-related isolation device.

The PCS generates control outputs based on sensor inputs and setpoints provided by the control system. The setpoints are adjusted automatically based on plant operating mode, or in some cases by operators via the main control room consoles. Plant Operators do not directly control PCS outputs.

4 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

7.3 Reactor Protection System

The RPS is the safety-related system credited with tripping the reactor and initiating protective functions upon receipt of signals in response to out-of-normal plant conditions. There are three possible sources that can cause the RPS to actuate:

Process variables reach or exceed specified setpoints as measured by safety-related RPS sensors that monitor core temperature, reactor coolant level, neutron flux, and the condition of the PHSS extraction line Manual initiation from the main control room or remote onsite shutdown panel Loss of plant electrical power (with a time delay)

Three protective functions result from RPS actuation:

Actuate the RCSS to insert control and shutdown elements into the reactor core Inhibit actions from the PCS so that it does not interfere with the functioning of the RPS, including RCSS element withdrawal, stopping the primary salt pump and heat rejection blower, stopping the pebble handling and storage system, and preventing the actuation of the reactor thermal management system Ensure the actuation of the Decay Heat Removal System

The RPS is built on a logic-based platform that utilizes discrete components and field programmable gate array technology

The RPS is isolated from non-safety related I&C Systems using safety-related isolation hardware Copyright © 2023 Kairos Power LLC. All Rights Reserved.

5 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

6 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

7.4 Main Control Room and Remote Onsite Shutdown Panel

The MCR contains equipment related to normal operation of the plant including:

Operator and supervisor workstation terminals, which provide alarm, annunciation, personnel and equipment interlocks, and process information from the PCS and RPS A manual trip switch that propagates through a gateway and safety-related isolation to allow operators to initiate a plant trip Central alarm panel for the fire protection system to monitor status of fire protection equipment in the Reactor Building and controlling the ventilation and extinguishing systems related for fire response

The Remote Onsite Shutdown Panel (ROSP) provides a human/system interface for plant staff to monitor indications from the RPS including the operating status of the reactor trip system and the decay heat removal system in the event the MCR becomes inaccessible or uninhabitable.

The ROSP features one-way (read only) communication with the RPS and the ability to initiate a manual trip signal that actuates the RPS.

7 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

Instrumentation and Controls Systems: Design Basis

The RPS and safety-related sensors are designed using relevant industry codes and standards such as IEEE 603-2018 and the quality assurance program (PDC 1)

The RPS and safety-related sensors are designed to withstand and be able to perform their safety-related functions during adverse natural phenomena (PDC 2)

The RPS and safety-related sensors are designed and located to minimize the probability and effects of fires and explosions (PDC 3)

The RPS is designed for the environmental conditions associated with normal operation, maintenance, testing and postulated events (PDC 4)

The RPS provides reactor trip and decay heat removal actuations that ensure radionuclide release design limits are not exceeded during normal operations, as a result of postulated events, and upon reactor trip actuation, including in the event of a single failure of the reactivity control system (PDCs 10, 20, 25)

The RPS, PCS, and safety-related sensors are designed to monitor plant parameters over the anticipated ranges of normal operation and postulated event conditions (PDC 13)

The design of the MCR (1) allows actions to be taken to operate the reactor under normal operating and postulated event conditions, (2) provides radiation protection allowing access and occupancy during postulated event conditions without personnel receiving radiation exposures in excess of 5 rem TEDE for the duration of the event, and (3) maintains habitability, allowing access and occupancy during normal operations and postulated event conditions.

The ROSP is located outside of the MCR and (1) provides the capability to promptly shutdown the reactor and monitor the unit during shutdown and (2) provides capability for subsequent safe shutdown of the reactor through use of suitable procedures (PDC 19)

8 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

Instrumentation and Controls Systems: Design Basis

The RPS and safety-related sensors are designed with sufficient redundancy and independence to assure no single failure results in a loss of protection function (PDC 21)

The results of natural phenomena, and of normal operating, maintenance, testing, and postulated event conditions do not result in loss of protection function of the RPS or safety-related sensors (PDC 22)

The RPS fails to a safe state upon loss of electrical power or detection of adverse environmental conditions (PDC 23)

The RPS and safety-related sensors are functionally independent from the non-safety related control systems (PDC 24)

The RPS setpoints are designed to limit the potential amount and rate of reactivity to ensure sufficient protection from postulated events involving reactivity transients (PDC 28)

RPS and safety-related sensors are designed to be redundant to assure there is a high probability of accomplishing the safety-related functions of the RPS in postulated events (PDC 29)

9 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

Hermes PSAR 8 Electrical Design A N T H O N IE CI LLI E RS - DI RE CTO R, I & C A CRS K A I RO S P O W E R SU BCO M MI TT E E M E E T I NG A P RI L 4 , 2 0 2 3 Copyright © 2023 Kairos Power LLC. All Rights Reserved.

1 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

2 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

8.2 Normal Power System

The normal power system does not perform any safety-related functions and is not credited for the mitigation of postulated events

AC power is distributed to the plant electrical loads during startup and shutdown, normal operation, and off-normal conditions

DC power supply is limited to I&C functions that require 24VDC for operations

The passive design features do not rely on electrical power for safety-related SSCs to perform their safety functions during postulated events (PDCs 17, 18)

The normal power system is designed so that differential displacements do not preclude a safety-related SSC from performing its safety function (PDC 2)

The normal power system is designed in accordance with National Fire Protection Association (NFPA) 70, National Electrical Code Copyright © 2023 Kairos Power LLC. All Rights Reserved.

3 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

8.3 Backup Power System

The backup power system (BPS) does not perform any safety-related functions and is not credited for the mitigation of postulated events

The BPS provides AC electrical power to essential loads when normal power is not available

The BPS includes:

Backup generators Automatically start in the event of offsite power One redundant generator by design Uninterruptible power supplies (UPS)

Highly reliable and continuous AC electrical supply Electrical equipment to connect the backup generators to the low voltage AC electrical power distribution Plug-in connection for a portable 480 VAC generator Copyright © 2023 Kairos Power LLC. All Rights Reserved.

4 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

8.3 Backup Power System: Design Basis

To ensure fail-to-safety in the event of a complete loss of AC electrical power, the reactivity control and shutdown system (RCSS) and the primary salt pump (PSP) relays require 24 VDC to remain closed On a loss of power, the RCSS relay opens, and the shutdown elements drop into the reactor by gravity On a loss of power, the PSP relays open to prevent inadvertent pump and blower restart on power restoration

On activation of the decay heat removal system, the reactor protection system will remove 24 VDC from the activation circuit relay to prevent inadvertent shut down of the DHRS by operator error

Equipment for monitoring reactor status will be supplied by UPS until the normal power supply or backup generators are restored

The passive design features do not rely on electrical power for safety-related SSCs to perform their safety functions during postulated events (PDCs 17, 18)

The BPS is designed so that differential displacements do not preclude a safety-related SSC from performing its safety function (PDC 2)

5 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

Hermes PSAR 11 Radiation Protection and Waste Management A U S T I N C LA R K - E N G I N E E R I I I , L I C E N S I N G A N D R E W L I N G E N F E LT E R - LE A D E N G I N E E R , E N G I N E E R I N G I N T E G R AT I O N ACRS K AIROS POWER SUBCOMMITTEE MEETING APRIL 4, 2023 Copyright © 2023 Kairos Power LLC. All Rights Reserved.

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11 Radiation Protection and Waste Management

This chapter defines the elements of the radiation protection program and the radioactive waste management program and systems Radiation Protection Includes identification of radiation sources, description of radiation protection program, description of ALARA program, radiation monitoring and surveying, radiation exposure control and dosimetry, contamination control, and environmental monitoring program Radioactive Waste Management Includes a description of the radioactive waste management program, and a description of radioactive waste handling systems and controls, design bases, and disposal of radioactive waste

For the PSAR, these programs are described at the commitment level. The PSAR commits to provide additional details at the operating license application stage, consistent with 10 CFR 50.34(b).

2 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

11.1 Radiation Protection

Radiation Sources Sources of radiation that present a potential hazard to workers and the public include fission products, decay products, fuel, and neutron activation products, including tritium

Radiation Protection Program The radiation protection program implemented for Hermes will comply with the regulatory requirements in 10 CFR 19 and 10 CFR 20, and will be developed, documented, and implemented commensurate with the scope and extent of licensed activities for a test reactor facility Program content and implementation will be reviewed periodically

ALARA Program A program to ensure occupational doses and doses to members of the public are as low as is reasonably achievable will be implemented as required by 10 CFR 20.1101 The ALARA program will be consistent with the guidance in Regulatory Guide 8.10 and the program description will be provided with the application for the operating license

Radiation Monitoring and Surveying Conducted as required by 10 CFR 20 to detect releases of radioactive material from facility equipment and operations Operational environmental monitoring is controlled by a radiological environmental monitoring program (REMP)

3 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

11.1 Radiation Protection

Radiation Exposure Control and Dosimetry Facility effluents are monitored for radioactivity during normal operations and postulated events Structures, systems, and components are designed to limit uncontrolled liquid or gaseous effluent releases to work areas or the environment A screening analysis of radioactive emissions from the facility employed:

the NRCs XOQDOQ and GASPAR II codes for dispersion and dose model calculations respectively site-specific, validated meteorological data covering a 5-year period of record a bounding tritium emissions rate set equal to the first-year tritium generation rate Total body effective dose equivalents from gaseous effluents were calculated for the plant site boundary, the location of the maximally exposed individual (MEI) in an unrestricted area, and an analytical nearest resident All modeled doses are below the limits specified in 10 CFR 20 Copyright © 2023 Kairos Power LLC. All Rights Reserved.

4 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

11.1 Radiation Protection

Contamination Control SSCs with the potential to contain/handle radiological materials include design considerations to limit leakage and control the spread of contamination and to facilitate eventual decommissioning consistent with the requirements in with 10 CFR 20.1406

Environmental Monitoring Radiation monitoring and surveys of radiation levels in unrestricted areas and radioactive materials in effluents will be conducted as required by 10 CFR 20.1302 An operational radiation effluent monitoring program (REMP) will be implemented considering the guidance in RG 4.1, Rev 2 and NUREG-1301 A description of the program will be provided with the application for an operating license The REMP will be implemented coincident with start of operation The existing site is already well characterized by Department of Energy to establish a baseline prior to Hermes operation Copyright © 2023 Kairos Power LLC. All Rights Reserved.

5 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

11.2 Radioactive Waste Management - Description

Radioactive waste management systems (RWMSs) are provided in the Hermes design for the collection, packaging, storing, and dispositioning of low-level liquid and solid radioactive waste (LLRW)

RWMSs functions include:

Decontamination capability for components and materials Vents and drains for the collection of liquid radioactive wastes Liquid radioactive waste handling Solid radioactive waste handling Copyright © 2023 Kairos Power LLC. All Rights Reserved.

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11.2 Radioactive Waste Management - Design Bases

The RWMSs are not credited to perform any safety-related functions

The design bases for the RWMSs include:

The RWMSs are designed so that seismic-induced failure does not impact the safety related SSCs (PDC 2)

The RWMSs are designed such that releases of radioactive materials to the environment do not exceed the limits of 10 CFR 20 (PDC 60)

The RWMSs are equipped with a radiation monitoring system to monitor effluent radiation levels (PDC 63)

The RWMSs are designed, to the extent practicable, to minimize contamination of the facility and the environment and facilitate eventual decommissioning consistent with 10 CFR 20.1406

Additional system description information will be provided with the application for an Operating License, consistent with 10 CFR 50.34(b)

7 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

11.2 Radioactive Waste Management - Program

Low-level radioactive waste (including all solid and some liquid radioactive waste) is expected to be packaged and disposed using a licensed and qualified LLRW disposal vendor

Gaseous radioactive effluents are filtered as practicable and monitored prior to release

Radioactive waste will be managed as prescribed by the radioactive waste management plan

Additional description of the radioactive waste management program will be provided with the application for an Operating License, consistent with 10 CFR 50.34(b)

8 No Reproduction or Distribution Without Express Written Permission of Kairos Power LLC.

ML23088A069

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