Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

My NLIT > CH-Charging and Letdown Subsystem > Flashcards

CH-Charging and Letdown Subsystem Flashcards

1
Q

What are the four RCS functions of the CVCS system?

A

RCS Chemistry&Purity, Inventory, Reactivity, and Pressure Control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the other four CVCS functions? Outside of RCS controls

A

Emergency Core Cooling, containment Integrity , Rx Coolant Leakage Detection, and Support Functions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does CVCS help RCS Chemistry and Purity Control?

A

Maintain chemistry for corrosion control
Contol system PH
Remove corrosion and fission products
Remove dissolved gases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does CVCS help RCS Inventory Control?

A

Replaces losses in containment due to small leaks. Provide makeup to RCS for safe shutdown using natural circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How Does CVCS help RCS with Reactivity Control?

A

Maintains Boron during normal power transients
Maintains Boron during core life to control temperatures.
Borate for safe shutdown during nat circ using only 1 charging pump
Inadvertent deboration can be detected b4 loss of shutdown marging
RWT can fill Refuel Pool and Transfer Canal in support of refueling.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How Does CVCS help RCS with Pressure control

A

Provides auxiliary PZR spray for manual control of pressure and PZR cooldown during final stages of plant shutdown and nat circ situations.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

During emergency core cooling which 2 signals will isolate the letdown line in containment?

A

SIA and CIAS will isolate the letdown line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the 3 support functions of the CVCS

A

Alt source of makeup from RMTW to SG via AF
Primary method of borated water from RWT to SFP
During SBO charging pumps maybe used to control RCS inventory when leaks <83 gpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the flow path of the Charging and Letdown Subsystem?

A

letdown>delay coils> Regenerative HX> Iso Valve> 1 or 2 Letdown control valves> LDHX> 1 of 2 Purification filters> Boronometer&Radiation Detector>IX>VCT>3 PDP Charging Pumps>Regenerative HX> Cold Leg RCP 2A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the purpose of the Delay coils?

A

Letdown flow via 2” to 2-16” pipes slow down Letdown flow. This allows ~95 sec delay to decay N-16 gammas w/i bioshield wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the purpose of Containment Isolation Valve CHB-UV-515?

A

Remain open to provide letdown flow, auto close of SIAS or Hi RGHX outlet temp of 413°, manually close to isolate letdown during letdown line break.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the purpose of containment isolation valve CHA-UV-516?

A

Remain open to provide letdown flow, auto close of SIAS or CIAS, and manually close to isolate letdown during letdown line break.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the purpose of the regenerative HX Outlet Isolation Valve CHB-UV-523?

A

Remain open to provide letdown flow and to auto close on CIAS or Hi LDHX outlet temp at 135°

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the cheat code for Valves 515, 516, and 523?

A

CHB-515 CHA-516 CHB-523
Hi-Si Si-Ci Ci-Hi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the characteristics of the Regenerative HX Isolation Valves?

A

They are air operated and fail closed on loss of air or power.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the purpose of the Regenerative HX

A

recovers heat from Letdown flow and transfers to charging flow stream for efficiency.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the design of the Regenerative HX?

A

It is a shell and u-tube HX Letdown flow on the tube side and charging flow on the shell side. Maintians letdown outlet temp below 413*.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the safety concern when working around the Regenerative HX?

A

Very high radiation during outages. Use time, distance, and shielding to minimize dose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the purpose of the letdown control valves?

A

Adjust letdown flow based on demand signal from the PZR level control system.
Reduce letdown press to ensure proper op of downstream components.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the design of the letdown control valves?

A

Air op and fail closed on a loss of air or power.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the automatic values of the PZR Level Control System (PLCS)?

A

Between 30-135 GPM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do the Letdown control valves work?

A

When RCS pressure is rising above 1000 psia ony one is inservice. When the RCS pressure is lowering from 1050 down both are inservice.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do the Letdown control bypass valves work?

A

If letdown is secured for more than 22 minutes the bypass valve allows .5gpm to flow for at least 4 minute to avoid thermal transient to plant components.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the purposed of the Letdown HX

A

Transfers heat from letdown flow to the Nuclear CW system to cool letdown to temp limits consistant with IX resins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the design of the letdown HX?

A

It reduces letdown flow temp from 413* to 110*F to prevent damaging the IX resin. Letdown in the tubes NC in the shell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the purpose of the Letdown Back Pressure Control Valves?

A

Controls intermediate pressure which ensures subcooled conditions in the LDHX.

27
Q

What is the design of the Letdown Back Pressure Control Valves?

A

Air op globe valves in parallel with 1 in op and one in standby. They maintain 375psig upstream and 40-95psig downstream. Auto isolate on Hi-Hi. Fail closed on loss of air.

28
Q

What is the purposed of the Letdown HX upstream and downstream pressure relief valves?

A

The LDLHX relief valve opens to protect downstream piping & components of the letdwn cntl valves. The purification filter inlet valve opens to protect downstream piping & components of the back press cntl valves.

29
Q

How do the RHX to LDHX relief valve operate?

A

The valve has a set point of 600 psig and will protect letdown blockage downstream
The purification filter inlet valve has a set point of 200 psig. Both valves discharge to EDT.

30
Q

What is the purpose of the Purification filters?

A

They remove insoluble particles from the letdown flow stream.

31
Q

What is the design of the purification filters?

A

They remove 98% of all particles 2 microns and larger. Must be replaced when D/P is <25 psid with max flow of 72 gpm or 5 Rem/hr

32
Q

What is the purpose of the RCS Letdown Radiation Monitor?

A

Monitors for fuel clad status.

33
Q

What is the design of the RCS Letdown Radiation Monitor?

A

Detects cladding failure by measuring the gamma radiation of the letdown passing by.

34
Q

What is the purpose of the valves controlling the flow to or bypassing the RCS Letdown Radiation Monitor?

A

The valve throttles letdown to provide flow past the monitor. It will also close on high temps so no letdown goes past monitor.

35
Q

What is the design of the valves controlling the flow to or bypassing the RCS Letdown Radiation monitor?

A

Monitors for fuel cladding damage. They are very temperature sensitive so bypass will close on hi letdown temp. The flow is 8gpm and the valve will fail open on loss of air or power.

36
Q

What is the purpose of the Purification Ion Exchangers Inlet/Bypass Valve?

A

Directs letdown flow through the CVCS Ion Exchanger during normal op. It will divert flow on hi temps so the resin doesn’t get damaged.

37
Q

What is the design of the Purification Ion Exchangers Inlet/Bypass Valve?

A

It is an air op 3way gate valve. Temps >135* will bypass IX. A loss of air or power will fail to divert flow around the IX’s

38
Q

What is the purpose of the CVCS Ion EXchangers?

A

There are 3 IX that are interchangeable. They are used for purification, delithiation, and deborating. They hold 35 cubic ft of resin and are make before break.

39
Q

Describe the Purification Ion Exchanger.

A

Mixed bed cation/anion conditioned with borated water and loaded with lithium to keep lithium levels in RCS stable. Always in service.

40
Q

Describe the Delithiating Ion Exchanger.

A

Mixed bed cation/anion normally in Standby only put in service when chemistry directs it. Normally on night shift for 15mins-several hrs. When lithium exhausted at end of life we reused then use for purification in next cycle.

41
Q

Describe the Deborating Ion Exchanger.

A

Anion resin bed normally used at the end of life to remove boron below 30ppm. Normally secured and tagged out.

42
Q

What is the purpose of the Volume Control Tank, Inlet Valve, and outlet valve?

A

The VCT provides surge volume for charging/letdown mismatches, required NPSH for charging pumps, means for adding hydrogen to RCS for scavenging oxygen, collects bleed-off from RCP seals, make-up point for the RCS. 4900 gal.

43
Q

Explain the cover gases in the VCT.

A

Hydrogen is added at power to scavenge oxygen to control the rate of corrosion of RCS. Nitrogen is added to VCT during shutdown to ensure oxygen does collect in the VCT.

44
Q

What are the VCT level set points?

A

A wet reference leg will divert flowto PHIX at 60% High and reset at 58%. At a lo-lo level of 5% the VCT outlet valve closes when level is at 15% valve will reopen.

45
Q

What are the VCT level set points?

A

A wet reference leg will divert flow to PHIX at 60% High and reset at 58%. At a lo-lo level of 5% the VCT outlet valve closes when level is at 15% valve will reopen.

46
Q

What controls VCT Level?

A

A dry reference leg control auto makeup to VCT. Not normally used. The RO normally maintains level while also maintaining reactivity.

47
Q

What types of makeup does the VCT have?

A

Blended-takes nonborated water from the RMWT and borated water from RWT to match concentration of makeup water to the reactor coolant.
Dilution-add non borated water from the RMWT to lower the boron concentration.

48
Q

What is the purpose of the charging pumps?

A

Provide charging flow from the VCT, RWT, or SFP for RCS makeup, Aux spray, RCS boration, or RCP Seal injection.

49
Q

What is the design of the Charging pumps?

A

3 cylinder, PDP, 44gpm at 2375 psig. The pumps run based on PZR level.

50
Q

What are the three modes for Charging Pumps?

A

Always running- always runs and no auto control from PZR level contrl systm (PLCS) can stop the pump.
Normal Running-normal runs a hi level signal in PZR auto stop the pump &restarts when cond clears.
Standby mode-not norm run lo level in PZR auto starts pump and stops when cond clears

51
Q

What are the power supplies for the charging pumps?

A

A & B are powered from their respective trains. The ‘E’ pump can be supplied by A/B train.

52
Q

How does the seal water system work with the charging pumps?

A

Lubricates the ppacking and controls leakage of reactor leakage of reactor coolant. Before start of charging pumps seal lube pump runs for 10 mins. Under ER you can run charging pumps for 50 hours without seal lube water.

53
Q

What does a suction stabilizer do?

A

Absorb pressure surges in the charging pump suction. The capacity is 10 gal and has a nitrogen bladder set to 19psig.

54
Q

What do pulsation dampeners do?

A

Dampen pulsation in the charging pump discharge. They have a nitrogen bladder at 1500 psig, spring loaded poppet, and a fixed flow diversion baffle.

55
Q

What is the function and interrelationship between the charging header outside containment isolaton valve backpress cntl valve, spring loaded bypass check valve, and Aux spray?

A

CHA-HV-524 is a 2” MOV as a committment to the NRC we keep the valve open and the breaker locked off/open.

56
Q

What is the Charging Line Backpressure Control Valve CHE-PDV-240?

A

Maintains backpressure for Aux spray, rcp seal injection, and to minimize charging pump pulsations.
Fails closed on loss of IA or power.

57
Q

What is the Charging Isolation Valve CHE-HV-239?

A

Opens to provide normal charging flow to RCS loop 2A through CHE-PDV-240. It can also close flow if 240 in not functional.

58
Q

What is the Spring Loaded Bypass Check Valve?

A

Opens to pass charging flow if 239&240 are closed. It maintains 200 psig of backpressure to ensure proper op of aux spray and RCP seal injection.

59
Q

What is the purpose of the Auxiliary Spray Valves?

A

CHB-HV-203 & CHA-HV-205 open to provide aux spray to PZR, closes to terminate spray flow and isolate the RCS from the charging subsystem.

60
Q

What is the design of the Aux Spray valves?

A

2” globe valves, solenoid opened and spring closed. They receive power from PKA/B-D21/22 and fail closed on loss of power. Loss of normal spray could be from loss of RCP’s or IA

61
Q

What is TRM LCO T3.2.102 Charging Pumps-Shutdown?

A

At least 1 charging pump, or 1 HPSI, or 1 LPSI in the boron injection flow path is required FUNCTIONAL.

62
Q

What is TRM LCO T3.1.103 Charging Pumps-Operating

A

At lease two (of three) charging pumps shall be FUNCTIONAL.

63
Q

What is TRM LCO T3.4.100 Auxiliary Spray System?

A

Both Aux spray valves (203&204) shall be functional.

My NLIT (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions