PZR/PRT

Question 1

State the functions on the pressurizer

Answer 1

H- Holds and maintains coolant pressure during stead state operation, preventing bulk boiling enabling coolant to remove core heat
E- Establishes normal operating pressure during startup
L- Limits the pressure changes caused by thermal expansion and contraction during plant transients to acceptable values
P- Prevents reactor coolant system from exceeding the safety limit value 2735#

Question 2

State the transients that the Pressurizer is designed to accommodate without causing a reactor trip

Answer 2

power increase or decrease of 5% per min with auto rod control
Instantaneous transients of +- 10% with auto rod control
Step load reduction of 50% of full power with auto rod control and steam dump operation.

Question 3

State Normal Temp/Press for PZR

Answer 3

650F

2235#

Question 4

State design pressure/ Safety valve set pressure

Answer 4

2485

Question 5

State PZR HU/CDR

Answer 5

HU: 100F/HR
CD: 200F/HR

Question 6

State Max spray water delta T

Answer 6

320F

Question 7

State RCS connections for PZR surge and spray lines

Answer 7

Surge: Loops 3 Hot Leg
Spray lines: loops 1 and 3: PCV-455B/ PCV-455A
Aux spray from CS-V-185 (charging line)

Question 8

State the functions of PZR spray bypass flow

Answer 8

Maintains the spray lines warm to prevent thermal stresses to spray lines and nozzle
Equalize boron concentration to prevent reactivity addition during outsurge

Question 9

State how the PZR responds on an insurge

Answer 9

Steam Demand goes down
Less heat removed -> Cold leg temp increases
Tave increases -> RCS expands into PZR compressing bubble
PZR pressure rises above saturation and bubble condenses which lowers pressure
Large insurge may cause spray actuation

Question 10

State how the PZR responds on an outsurge

Answer 10

Steam demand increases
More heat removed -> Cold leg temp decreases
Tave decreases -> RCS contracts and flows from PZR
PZR level decreases and bubble expands
Pressure drop causes liquid to flash to steam which increases pressure
Large outsurge may energize heaters

Question 11

State methods used to limit temperature in the PRT

Answer 11

Flow enters the PRT through the sparger which is under water

PRT has a pump and HX which cools PRT contents, auto on <120F

Question 12

Discuss N2 blanket in PRT

Answer 12

Prevents introduction of air to minimize corrosion of the tank
Prevents build up of explosive H2

Question 13

Discuss PRT auto recirculation

Answer 13

PRT pump auto starts at 120F

Pump switch much be in auto and transfer switch must be in recirc

Question 14

State T.S. 3.4.2.1 (RCS Safety Valves - Shutdown) LCO and Actions

Answer 14

A minimum of 1 PZR Code safety valve shall be OPERABLE with a lift setting of 2485# +- 3%
MODE: 4 and 5
With no PZR Code safety valve OPERABLE, immediately suspend all operations involving positive reactivity changes and place an OPERABLE RHR loop into operation in the shutdown cooling mode

Question 15

State PRT rupture disk setting

Answer 15

91#

Question 16

State T.S. 3.4.2.2 (RCS Safety Valves - Operating) LCO and Actions

Answer 16

All PZR Code safety valves shall be OPERABLE with a lift setting of 2485# +- 3%
MODES: 1,2, and 3
With one PZR Code safety Valve inoperable, either restore the inoperable valve to OPERABLE status within 15 minutes or be in at least HOT STANDBY within 6 hrs and in at least HOT SHUTDOWN within the following 6 hrs

Question 17

State T.S. 3.4.3 (Pressurizer) LCO and Action

Answer 17

The PZR shall be OPERABLE with a water volume of less than or equal to 92% and at least two groups of PZR heaters each having a capacity of at least 150kW and capable of being powered from an emergency power supply
MODES: 1,2, and 3
b. With the PZR otherwise inoperable, fully insert all rods, place the Control Rod Drive System in a condition incapable of rod withdrawal, and be in at least HOT STANDBY within 6 Hrs and in HOT SHUTDOWN within the following 6 Hrs

Question 18

State T.S. 3.4.4 (Relief Valves) LCO and Action

Answer 18

Both power-operated relief valves (PORVs) and their associated block valves shall be OPERABLE
MODE: 1,2 and 3
With one or both PORVs inoperable within 1 hr either restore the PORVs to OPERABLE status or close the associated block valves(s)