Verification and Validation

DOE-STD-6002-96

The safety analysis shall show that the set of PIEs bounds credible anticipated opera-

tional occurrences and off-normal conditions that influence the safety of the facility. The PIEs

and their consequences shall be analyzed and categorized so that a subset of bounding or limit-

ing events from each category (i.e., anticipated operational occurrences and off-normal condi-

tions) can be selected for detailed quantitative analysis as part of the design basis. Off-normal

conditions beyond the design basis should be analyzed for the purpose of emergency planning

and to ensure that there are no events with probabilities near the limit of credibility with conse -

quences that are much larger than those for the worst credible events.

A combination of probabilistic and deterministic approaches may be used in the safety

analysis. Probabilistic approaches may be used to gain insight and to help establish events

within the design basis as discussed in Section 4.3. When probabilistic approaches are used

and data are scarce, conservative estimates shall be used and the rationale for their use shall

be documented. These estimates may be based on inference from similar equipment, expert

opinion, detailed analyses (such as probabilistic fracture mechanics), existing fusion experience,

or other means. Deterministic analyses shall specify the assumptions used in the assessments

(i.e., input parameters, initial conditions, boundary conditions, assumptions, models, and codes

used) and the level of conservatism (i.e., safety margin) in the assessment. Results of these

complementary approaches provide input into the design process of the facility.

4.11 Verification and Validation

The applicability of the design and safety analysis methods shall be verified and the

methods validated. Furthermore, an equipment qualification procedure shall be established for

items performing public safety functions to confirm that the equipment is capable of meeting the

safety functions for the facility while subject to the environmental conditions (e.g., vibration,

temperature, pressure, jet impingement, radiation, humidity, chemical attack, and magnetic

fields) existing at the time of need. Experimental data used in the design process or in the safety

analysis shall undergo formal validation.

4.12 Special Considerations for Experimental Use

Fusion facilities, especially those considered test facilities, may by their nature include

experimental component modules or equipment. As a general rule, experimental systems

should not be expected to perform safety functions. However, if such components are required

to perform a safety function, the safety analysis must show that potential faults in experimental

equipment shall not cause evaluation guidelines to be exceeded. The flexible nature and

changing states of the system also require special precautions to be taken in the design and

operation to minimize the effects of human error.

Experimental equipment shall be designed so that in each operational state it cannot

cause unacceptable consequences to the facility, other experiments, workers, or the public.

Specific considerations include but are not limited to the following:

a. factors in experiments that could cause a breach of any confinement barrier;

b. factors in experiments that could adversely affect items performing safety functions;