Methodology - doe-std-3009-94_cn3

DOE-STD -3009-94

3.4.1 Methodology

This section summarizes the methods used to quantify the consequences of

operational accidents, natural external events, and man- made external events

selected in Section 3.3.2.3.5, "Accident Selection." Identify and describe any

computer programs used to implement methods discussed below. Include in the

description the origin of the code, its precedent for use, input data, the range of

variables investigated, the basic analytical models, their interrelationships, and

the progression of the analysis. Briefly summarize and reference detailed

information on algorithms, computational and analytical bases, a nd software

quality assurance measures.

Documentation of methodology should include the following:

Methods used to estimate radiological or other hazardous material source

terms for DBAs including: (1) basic approach for estimating physical

facility damage from DBAs; (2) general basis for assigning material-atrisk

quantities not directly derived from hazard identification, if differing

values are used; and (3) basis for material release and respirable fractions

or release rates used.

Methods used to estimate dose and exposure profiles including

assumptions on variables such as meteorological conditions, time

dependent characteristics, activity, and release rates or duration for

radioactive or other hazardous materials that could be released to the

environme nt.

3.4.2 Design Basis Accidents

This section analyzes DBAs for each of the major categories to quantify

consequences and compare them to the Evaluation Guideline. The major

categories are: internally initiated operational accidents (e.g., fires, explosio ns,

spills, criticality); natural events for the site (e.g., earthquakes, tornadoes) that

could affect the facility; and man- made externally initiated events such as

airplane crashes, transportation accidents, adjacent facility events, etc., that can

either cause releases at the facility under examination or have a major impact on

facility operations. Beyond DBAs are discussed in Section 3.4.3, "Beyond

Design Basis Accidents."

Quantification methods are typically limited to calculating the dose profile of a

release. The process is iterative, starting by taking no credit for mitigative

features and comparing results to the Evaluation Guideline. Continue taking

credit for additional mitigative features incrementally and comparing the results

to the Evaluation Guideline until below the guideline. This iterative process,

however, does not require denying the physical design of facility structures,

systems, and components. For example, if liquid hazardous material is brought

into a facility in steel piping and stored in steel tanks, it is not meaningful to

disregard the existence of these physical features in analysis. Simply admitting

they exist does not require safety-class SSC designation either. Stated another

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