Set 4

Question 1

• Probabilistic Risk Assessment*
• • *

What are the risk important operator actions?

Answer 1

Manually start idle CRE HVAC train

Start RHR train

Start standby trains after loss of SSPS due to fire.

Perform bleed and feed for loss of heat sink general transient event.

Start PDP after LOOP

Question 2

• Probabilistic Risk Assessment*
• • *

What are the level 1 PRA external events?

Answer 2

Fire

Flooding

Tornado

Seismic

Question 3

• Probabilistic Risk Assessment*
• • *

What is the level 1 PRA top vulnerability?

Answer 3

LOOP

Question 4

• Probabilistic Risk Assessment*
• • *

What are the levels of PRA?

Answer 4

• Level 1:*
• *Core Damage**
• CDF / year*
• Level 2:*
• *Large Early Release of Radiation**
• LERF / year*
• Level 3:*
• *Public Health Consequences**
• Early and Late Casualties / year*

Note:
STP does not have level 3 b/c industry standards do not require it.

Question 5

• Probabilistic Risk Assessment*
• • *

When is a shutdown risk assessment used?

Answer 5

During Refueling Outages

Mid-Loop Outages

Non-Refueling Outages ≤ MODE 5

Determined by Plant General Manager

Question 6

• Probabilistic Risk Assessment*
• • *

Who performs the final approval of the shutdown risk assessment report?

Answer 6

Plant General Manager

Question 7

• Probabilistic Risk Assessment*
• • *

What is most likely to cause an early large area release? (Level 2 PRA)

Answer 7

Induced SGTR