Safe Shutdown

FRS – Safe Shutdown

Safe shutdown (SSD)

With an electrical distribution diagram and system flow diagrams already built in GLASS, equipment can be logically related to cable routings and fire areas to develop and document safe shutdown fire area strategies to meet regulatory compliance with 10 CFR 50 Appendix R, NUREG-0800, or NFPA 805. FRS-SSD can assist with identifying simplified approaches to mitigating a scenario using a minimal set of recovery actions outside of the control room or alternative recovery actions that may restore more redundancy to challenged systems.

FRS-SSD provides an interactive safe shutdown analysis that is understandable and easy to use. FRS-SSD provides diverse functionality including the ability to perform and document:

  • Safe shutdown analyses by fire area (or fire scenario to support the Fire PRA)
    • Equipment-cable analyses
    • Equipment-cable resolutions
  • Recovery actions Protected Raceways (ERFBS)
  • Customized Reports
  • Provide basic event mapping for input into Fire PRA Quantification


Fire area summary annunciator panel

GLASS Safe Shutdown
A Fire Area Summary Annunciator Panel provides the current plant status based on selected scenarios and equipment unavailability. RED indicators highlight where plant challenges exist.

Developing a facility’s safe shutdown analysis inside FRS provides a simplified yet comprehensive approach in an interactive setting where the graphical logic assists with documentation and ongoing program maintenance. ‘What-If’ scenarios provide a unique look at all possible options available to the safe shutdown team. Building a facility’s safe shutdown analysis inside FRS provides a methodology that understands the importance of each recovery action. FRS confirms which actions are required for safe shutdown and which actions provide redundant support.

Additionally, FRS-SSD provides an intuitive graphical interface to assist with:

  • Understanding not only the credited success path for compliance, but all possible success paths, providing enhanced understanding of operational and equipment impacts to the SSD analysis.
  • Tracking out of service (OOS) equipment and their impacts on credited SSD compliance strategies.
  • Understanding the appropriate compensatory measures when equipment is OOS.
  • Understanding power supply dependencies.
  • Understanding performance goal success logic and failures that impact performance goal success.
  • Visualizing conceptual design modifications prior to implementation.


Electrical distribution model

SSD electrical
An Electrical Distribution Model indicates power supply impairments due to the scenario, and provides a detailed understanding of where challenges to power supplies exist.

System flow diagram

SSD system
System Flow Diagrams indicate system and equipment impairments due to the scenario. The graphical display identifies where plant challenges exist, allowing for rapid assessment and decision-making to implement effective compliance strategies.
PFP - nuclear facility

Facility response

Depicts system and equipment status in user-familiar formats.

FRS brochure

FRS brochure

Download the Facility Response Simulation (FRS) brochure.

Customizable FRS

Customizable FRS

Symbols and layouts can be customized to meet user preferences.

GLASS commercial nuclear

FRS – commercial nuclear

Planning, engineering, rad protection, operations and security.



Provides real-time evaluation into potential radiation exposures.



Mitigation strategies for beyond-design-basis external events.

GLASS surveillance module

PFP – surveillance module

Directly record surveillance data from field walk-downs into a portable device.