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Critical Tasks - Simulator Scenario Development Brian Tindell Acting Chief - Operations Branch Region IV Brian.Tindell@nrc.gov

Agenda

The NRC prescribes uniform conditions for licensing.

A CT must be safety-significant for the specific plant and specific scenario.

CT Element 1: A cue

CT Element 2: Feedback

CT Element 3: A success path

CT Element 4: Expected actions and documented objective boundaries

Boundary conditions (goal lines) define success and define failure.

Feedback is NOT required for Boundary Conditions.

Set the goal line for competent applicants, not heroes.

The crew must be able to fail.

Try to write preferred boundary conditions

Alternative boundary conditions are acceptable.

Document an objective justification for boundary criteria, especially alternative BC.

Critical Task Example 1

Critical Task: Un-isolable Torus water leak and unable to maintain Torus level above 10.75. HPCI must be tripped before Torus water level lowers below 9.58.

Critical Task Example 1

Safety Significance: HPCI operation with Torus water level below 10.75 would result in introduction of steam from the HPCI exhaust into the Torus airspace

Critical Task Example 1 Boundary Conditions?

Measurable Performance Standard: Manipulation of the HPCI trip pushbutton will provide observable actions for the evaluation team.

Justification?

Critical Task Example 2

-Isolate SG

-Cooldown RCS

-Depressurize RCS

Critical Task Example 3

Critical Task Example 4

CT at Facility #1: Isolate ruptured SG within 15 minutes of inadvertent opening of dump valve. (Criteria for SAE)

CT at Facility #2: Isolate ruptured SG within 70 minutes of entry into tube rupture procedure. (FSAR assumption)

Critical Task Example 5

An applicant inadvertently causes an SBO (not a post-scenario CT), and the plant automatically starts a cooldown (was going to be the CT). What do you do?

Thanks! Questions?

ML26037A166