analyses to confirm assumptions used in the derivation of TSRs and to verify inventory certainties. Once
the six process vessels were removed and all required confirmations and approvals completed, the
limiting conditions of operations (LCOs) contained within the TSRs that were associated only with this
"mode" were no longer applicable. Additional TSRs were applicable during the subsequent "mode,"
including more detailed characterization of the pipe trench. Hold points were used throughout the
activities to ensure that assumptions, laboratory data, analyses, and approvals were obtained prior to
Example 13: Tailoring of Unreviewed Safety Question Process to Environmental Restoration
The Unreviewed Safety Question (USQ) process has retained the focus on protecting hardware that is
important to safety (Equipment Important to Safety). This example provides one way that responses to
the USQ questions on Equipment Important to Safety have been tailored to fit ER activities.
DOE G 424.1-1, Implementation Guidance for Use in Addressing Unreviewed Safety Question
Requirements, identifies seven questions that are an expansion of the three general questions identified in
10 CFR 830, Subpart B. Standard questions # 3 (probability of a malfunction of equipment important to
safety), # 4 (consequence of malfunction of equipment important to safety), and # 6 (malfunction of
equipment important to safety of a different type) all involve the issue of change impact to hardware
(equipment important to safety). These questions are focused on some form of hardware barrier
mitigating an undesirable event. Environmental restoration activities typically have a stronger reliance on
administrative controls and company level safety management programs as opposed to safety SSCs
Recognizing that administrative controls can provide a level of importance similar to that of safey SSCs
(see DOE-1186), one DOE site expanded their responses to USQD questions to better fit ER activities.
The responses address the standard "equipment important to safety" (e.g. there are none) and expand the
response to cover "controls important to safety" that replace the traditional hardware reliance. A typical
response to question # 3 is provided below as an example of the tailoring that has been used.
(3) Could the proposed change or as-found condition increase the probability of a malfunction of
equipment important to safety previously evaluated in the facility's safety analyses?