Accident Stresses

DOE-HDBK-3010-94

1.0 Introduction

bounding ARFs and RFs. The purpose of developing these values was (1) to better

understand the potential bounding hazards presented by nonreactor nuclear facilities, and

(2) to provide information to support general bases of decisionmaking. The first purpose has

been fulfilled by use of this information in the Defense Programs Safety Survey Report

(Pinkston, et al., 1993). This use has supported previous NRC estimates that the bounding

consequence potential for nonreactor nuclear facilities is significantly less than commercial

nuclear power plants, or large commercial chemical plants as well. In domino fashion, this

conclusion has reemphasized the use of the term "general bases" in the second purpose. The

information in this handbook can be used to indicate relative significance of unmitigated

releases and to verify the effectiveness of mitigative measures, such as HEPA filtration. It is

a misuse of information in this handbook to focus on ARF "pencil-sharpening" at the expense

of objective, performance based evaluation, particularly to attempt subtle judgements of

consequence potential to support fine distinctions such as testing HEPA filters to only 90%

efficiency, or to claim that meeting a dose guideline alone using this data constitutes a

complete safety basis.

1.4

A C C I DE N T S T R E S S E S

In developing this handbook, literature and historical experience on the major types of

accidents in nonreactor nuclear facilities were reviewed. The evaluation of experimental data

was then focused on identifying applicability for those accidents. High-energy insertion-type

events that are of concern for nuclear reactors are not covered by this document, nor are

some accident conditions peculiar to high-level waste tanks (e.g., response of salt or moist

salts to accident-generated conditions). Some responses of materials found in high-level

waste vitrification plants to accident stresses are directly covered (e.g., brittle fracture of

glasses due to crush-impact, free-fall spill of liquids and slurries), but others (e.g., behavior

of molten salts and glass) are not. In some cases, attempts can be made to bound such

materials by using data for more limiting materials. As with extrapolation, care should be

used in any such attempt.

The main types of accidents of common concern in nonreactor nuclear facilities are:

S p ill: Material experiences instability/shear stress at the surface of the mass

resulting in sub-division of the overall mass. Airflow patterns around and

through the material mass, including induced turbulence, accelerate overall

sub-division. Mass breakup is further enhanced by impact with ground

surface. The material sub-division can generate particles sufficiently small that

they remain airborne for a significant period of time.

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