Tritium Systems - hdbk60040047

DOE-HDBK-6004-99

basis (or Graded Approach) should specifically describe the requirements for coupling PIE and

internal transients; the influence of PIE on parameter measurements, uncertainties and response times

should be evaluated for those scenarios requiring coupling of events.

Monitoring of the inventory levels and barrier integrity should address the Postulated Initiating Event

of concern. Active detection and venting to expansion volumes must meet the response times

assumed in the analysis criteria. Passive designs for channeling coolant to the expansion volume

should be considered.

TRITIUM SYSTEMS

General Safety Design Criteria

Tritium system tritium system design should include features which minimize the environmental

release of tritium and exposure of personnel, minimize quantities of tritium available for release during

accidents or off-normal events, and minimize the unintended conversion of elemental tritium to an

oxide form. Consistent with facility safety analysis, design features should include:

1. Segmentation of the tritium inventory such that release of all tritium from the single largest

segmented volume has acceptable consequences,

2. Confinement barriers1 to reduce tritium environmental release to an acceptable level,

3. Materials and equipment which are tritium compatible and minimize exposure of tritium to

oxygen, and

4. Cleanup systems to recover gaseous tritium released within any confinement barrier or to process

streams exhausting to atmosphere.

Tritium system functions should be designated safety functions if they are credited in the facility safety

analysis in order to meet prescribed safety criteria. Systems or components needed to perform safety

functions should be designated safety-class systems or components. Components which do not

perform safety functions but whose single failure causes the failure of a safety function should be

designated safety-class components.

Generic System Description

The following sketch illustrates the tritium system consisting of five major functional areas within

multiple confinement barriers:

Primary confinement, a sealed system rated for design maximum pressure and low leak rate, is the

This document considers the tritium containment system to be a type of confinement. Sealed high-

integrity process equipment and piping provide the containment system, for vacuum and pressure conditions,

and constitute the primary confinement barrier. The secondary confinement barrier consists of gloveboxes and

cabinets which house the primary confinement (containment) system. To complete the secondary

confinement, process piping between glove boxes or cabinets are within a jacket enclosure which seals to the

glovebox or cabinet. Additional sealed cabinets or rooms may extend the concept to tertiary, quaternary or

higher orders of confinement in accordance with the facility' safety analysis.