Reactor Protection System

Question 1

What is the non-safety related functions of the reactor protection system?

Answer 1

Initiate a turbine trip from a reactor trip signal.

Provide the status and alarm conditions of input signals to the SSPS and the status of output signals from the SSPS.

Question 2

What two things would the reactor protection system trip the reactor on to protect against over pressurization?

Answer 2

Pressurizer pressure high

Pressurizer water level high

Question 3

What are the results of an AMSAC actuation?

Answer 3

Turbine trip.
MDAFP start.
TDAFP start.
Aux feed flow conservation initiation.

Question 4

What causes a Safety Injection?

Answer 4

1.0 psig in lower containment.
Pressurizer pressure low 1775 psig.
Steam line low pressure 500 psig.
Steam line D/P 100 psid.
Manual.

Question 5

Does an phase A give you a SI

Answer 5

No

Question 6

Does an SI give you a phase A

Answer 6

Yes

Question 7

Describe the safety-related 4kv bus under voltage signal?

Answer 7

The circuitry detects a rapid voltage drop on any of the 4kv T-busses. After a two second time delay it performs a load shed on that bus.

Question 8

Describe what happens when you get degraded voltage on a safety-related 4kv bus.

Answer 8

When voltage falls to 113 on two of three phases on A or D T-bus a 9 second timer starts. If after the 9 seconds the condition still exists then a 90 sec. Timer and a 111 sec. Timer starts. After the 90 sec. Timer times out it transfers the auxiliaries to the RAT’s. After the 111 sec timer times out if the condition still exists it opens the tie breakers to the RCP bus and start the AB EDG.

Question 9

What is the purpose of the reactor protection system?

Answer 9

To protect the reactor and RCS from over pressure and over temperature.

Question 10

What is departure from nucleate boiling?

Answer 10

The formation of a layer of steam or a film on the fuel slowing the transfer of heat from the fuel to the RCS.

Question 11

When can you move rods?

Answer 11

When both reactor trip breakers are racked in and one MG set is in service

Question 12

What must be met before starting the first MG set

Answer 12

T.S. must be met.

Question 13

What is the safety related functions of the reactor protection system?

Answer 13

Keep the fuel within minimum departure from nuclear boiling ratio (DNBR) design limits.

Assist in limiting RCS pressure to within design constraints.