Instrumentation and Controls

DOE-HDBK-6004-99

Tritium Embrittlement

The structural design analysis should use material properties based on tritium and helium

embrittlement for the projected end-of-life.

Penetrations of Confinement Systems

Penetrations should meet the same materials requirements as the penetrated confinement system.

Instrumentation and Controls

Tritium systems design should provide for instrumentation and control to monitor parameters

important to the safety function for normal operation and design basis accidents. The safety analysis

should identify and the design should implement:

1. Instruments to monitor safety-related variables. Primary confinement will typically provide

monitoring for pressure, vacuum, temperature, and the ability to provide batch-based qualitative

gas analysis. Secondary confinement will typically provide for tritium detection, pressure (relative

to ambient or tertiary confinement), and oxygen level (if secondary has a reduced oxygen

atmosphere). Subsequent levels of confinement will provide monitoring abilities commensurate

with the hazard anticipated and the operating conditions of the barrier.

2. Controls to maintain measured variables within prescribed limits and to isolate tritium subsystems

when necessary for safety reasons.

3. The design for safety-class systems, including their ventilation systems, should incorporate

sufficient redundancy and/or diversity to ensure that a single failure will not result in total loss of

instrumentation or control for a safety function.

The power supply for safety-class instrumentation and controls should meet the requirements for

Class 1E electric power systems (IEEE 308).

The different designs and operating characteristics of fusion facilities limit the amount of specific

guidance that these criteria can provide. Existing DOE and NRC design requirements and guidance

documents (IEEE 603, DOE 6430.1A, NUREG-0800, 10CFR50(A), USNRC Regulatory Guides

(RG 1.100 - RG 1.89)) provide helpful general guidance for implementing these criteria at a particular

fusion facility.

Confinement Systems

Tritium systems design should provide for confinement barriers to reduce tritium releases to an

acceptable level. The safety analysis should define and the design should implement appropriate

robustness and leak tightness for the barriers. The confinement system should include as a minimum

primary confinement system and a secondary confinement system. Design should also provide for

tertiary, quaternary or higher orders of confinement if the safety analysis indicates these higher orders

are necessary. The assumption of a single failure within the system does not compromise the

confinement function.