Design Considerations - hdbk60040044

DOE-HDBK-6004-99

ANSI/ANS 3.8.5-1992

Criteria for Emergency Radiological Field Monitoring, Sampling, and Analysis

ANSI/ANS 3.8.6-1995

Criteria for Conduct of Offsite Radiological Assessment for Emergency Response

for Nuclear Power Plants

IEEE 730

Software Quality Assurance Plans

IEEE 829

Standard for Software Test Documentation

IEEE 830

Guide for Software Requirements Specifications

IEEE1012

Standard Software Verification and Validation Plans

IEEE 1016

Recommended Practice for Software Design Descriptions

IEEE 1042

Guide to Software Configuration Management

IEEE 1063

Standard for Software User Documentation

Design Considerations

Diversity

In the selection of the sensors and measuring systems for the in-vessel and near vessel parameters,

multiple diverse technologies should be implemented since these instrument components will be

exposed to harsh environments (potential radiation exposure, magnetic fields, temperature gradients,

ion pulses, etc.) Unexpected failure mechanisms within a single measurement technology could lead

to erroneous control or safety actions. Provision for the use of diverse measurement technologies

in the design would provide alternative sensing capabilities and reduce the possibility of failure to

detect and initiate a safety function due to common mode or common cause failures.

Graded Approach to Defense In Depth

The failure consequence and frequency of the PIE should be considered in the determining the degree

of the redundancy and diversity required in the I&C system. Anticipated operational events of high

consequence should require an analyzed probability of successful action. This analysis should include

the presence of an undetected failure in the safety related I&C system equipment necessary to

accomplish the required safety function. Events of lower frequency and/or consequence may be

shown to be mitigated by less rigorous analysis and subsequently less rigorous I&C equipment

requirements.