Derivation of Technical Safety Requirements
PURPOSE. The purpose of this DSA chapter is to provide information necessary to
support the safety basis requirements for the derivation of hazard controls in 10 CFR
This chapter builds upon the control functions determined to be essential in Chapter 3,
"Hazard and Accident Analyses," and Chapter 4, "Safety Structures, Systems, and
Components," to derive TSRs. This chapter is meant to support and provide the
information necessary for the separate TSR document required by 10 CFR 830.205.
Derivation of TSRs consists of summaries and references to pertinent sections of the
DSA in which design (i.e., SSCs) and administrative features (i.e., non-SSCs) are
needed to prevent or mitigate the consequences of accidents. Design and
administrative features addressed include ones which: (1) provide significant defense in
depth; (2) provide for significant worker safety; or (3) provide for the protection of the
public. Expected products of this chapter, as applicable based on the graded approach,
Information with sufficient basis from which to derive, as appropriate, any of the
following TSR parameters for individual TSRs:
-- Safety Limits (SLs).
-- Limiting Control Settings (LCSs).
-- Limiting Conditions for Operation (LCOs).
-- Surveillance Requirements (SRs).
Information with sufficient basis from which to derive TSR administrative
controls for specific control features (SACs) or to specify programs necessary to
perform institutional safety functions.
Identification of passive design features addressed in the DSA.
Identification of TSRs from other facilities that affect the facility's safety basis.
Existing support documentation is to be referenced. Include brief abstracts of
referenced documentation with enough essential facts to provide an understanding of
the referenced documentation and its relation to this chapter.
APPLICATION OF THE GRADED APPROACH. Hazard Category 2 and 3
facilities include TSR information based on material detailed in Chapters 3 and 4. For
Hazard Category 3 facilities, TSRs may consist solely of an inventory limit to maintain
the Hazard Category 3 classification and provide appropriate commitments to safety
programs in the administrative controls section of TSRs.
It can be expected that Hazard Category 2 facilities will have more TSRs than Hazard