Brainscape's Knowledge GenomeTM

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


See full index

Block 2 > Reactor Vessel and Internals > Flashcards

Reactor Vessel and Internals Flashcards

1
Q

Discuss Reactor Vessel Construction.

A
  • 14.3’ ft diameter.
  • Welded Carbon Steel plates clad internally with 5/16” SS-304 (for corrosion resistance)
  • Ledge in vessel supports weight of internals which is transferred to nozzles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Discuss Reactor Vessel Closure Head.

A

Low Alloy Steel.
* Bolted to, and supported by the Rx vessel by 54 – 7” diameter threaded studs, washers, and nuts
* Studs “stretch tensioned” to develop clamping force, nuts run against flange then tension is removed
* 2 alignment pins aid in precise alignment of head on flange
* 74 [102] penetrations total; 8 [10] for instrumentation; 1 for vent

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

Discuss Reactor Vessel Closure Support Structure.

A

Beams embedded in the concrete over 1 Hot Leg and Two Cold Legs

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

Discuss Reactor Vessel Flange/Head ‘O’ Rings.

A
  • Consists of 2 “O” Rings (inner and outer) that fit in 2 concentric grooves in head flange
  • Inconel tubing, coated with pure silver
  • Holes in vessel flange between O-rings ported to pressure indicator (local) and switch
  • Leakage past inner O-ring pressurizes the space and is detected by PI and switch
  • Local gauge and Rx Head Seal High Pressure Alarm (~2000 psia [~1000 psig] -RTGB)
  • If alarm clears it is indication that outer O-ring may have failed. Can be reversed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Discuss Reactor Vessel Insulation.

A

Limits RCB (CNMT) temperatures by limiting the heat loss from the RCS to CNMT

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

Discuss Reactor Flow Skirt.

A

Inconel
* Equalizes flow and pressure across the core support barrel
* Sits on very bottom of vessel

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

Discuss Reactor Vessel Weight Transfer.

A
  • Vessel is supported by steel pads welded to the underside of nozzles (B1-Th, A1/A2-Tc)
  • Pads sit on steel girder columns (support structures) which permits radial expansion (thermal growth), maintains centering, and restrains seismic induced motion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Discuss Reactor Core Barrel.

A

Suspended from a ledge on the inside surface of the Rx vessel flange and supports the entire weight of the Rx Vessel Internals

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

Discuss Reactor Core Stops.

A

Inconel
* 9 core stops limit the downward motion (fall) of the core support barrel should the support ledge fail

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

Discuss Reactor Core Support Plant (Assembly).

A

SS-304
* Aligns the fuel assemblies via locating pins and directs coolant flow into the fuel
* Transfers the weight of internals to the barrel

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

Discuss Reactor Core Shroud.

A

SS-304
* Surrounds core to limit bypass flow (square fuel, round hole)
* Flow holes in support plate allow bypass flow to minimize thermal stresses b/w barrel and shroud

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

Discuss Reactor Upper Guide Structure (UGS) & Support Plate.

A
  • Supports the upper end of the fuel assemblies to prevent movement.
  • Provides hold down force to prevent core uplift due to coolant flow forces
  • Supported by the Rx vessel flange.
  • Supports the ICI plate assembly, CEA shroud, and ICI guide tubes
  • Fuel Alignment plate on bottom of UGS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Discuss Reactor CEA Shrouds.

A

Austentitic SS
* Guides CEA’s through fuel alignment plate

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

Discuss Reactor Instrument Plate (ICI Plate).

A

Provides a guide path for Incore detectors

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

Discuss the Reactor Core.

A
  • 217 Fuel Assemblies
    o Gadolinium is the burnable absorber used for fuel. (Homogeneously integrated into fuel pellets)
  • 73 [87] CEA’s.
    o {Unit 1 has 73 CEAs but 12 SD CEDMs are duals (control 24 CEAs). Thus 61 CEDM extension shafts operate 73 CEA’s}
    o B4C is the absorber used in CEAs.
  • 14X14 [16X16] fuel pins per assembly (Zircaloy tubes with low enrichment UO2)
  • [16X16 matrix for Unit 2 fuel assemblies gives us more linear feet of fuel rods which Reduces the Peak Linear Heat Rates on Unit 2]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Discuss Reactor Core Bypass Flow.

A
  • Total: ~4.2% [2.54%]
  • Guide Tube - 1.61% [1.29%] 43-48% (**MAJOR CONTRIBUTOR **)
17
Q

Discuss Reactor Vessel Sampling Package System.

A
  • Test specimens used to determine the effects of irradiation on vessel materials
  • 6 capsules are located in the Core Support Barrel. Analysis of these specimens is used to establish the permissible Nil-Ductility Transition Temperatures for the Rx
18
Q

Discuss Reactor Refueling Sequence.

A
  • Shutdown and Cooldown Unit to Mode 5 conditions
  • Remove interference
  • Permanent cavity seal ring - only need to close hatches
  • De-tension head studs (Mode 6),
  • Remove Head and set on 62’ elevation,
  • Unlatch CEA’s
  • Install UGS lift rig and remove UGS and from vessel and place in lower cavity,
  • Perform core off-load or fuel shuffle,
  • Re-assembly is reversal of sequence described.
19
Q

Which ONE of the following components does NOT receive direct support from the Rx Vessel Flange?
a. Core Barrel
b. Shroud
c. RV Closure head
d. Upper Guide Structure

A

b. Shroud

20
Q

Which ONE of the following best describes the Reactor Vessel Support Structure?
a. Supported by all 4 Cold legs
b. Supported by Both Hot Legs
c. Supported by 1 hot and 2 cold legs
d. Supported by a ledge in the RV Flange

A

c. Supported by 1 hot and 2 cold legs

21
Q

Describe how the integrity of the reactor vessel and internals are protected by Tech Specs?

A

Safety Limits, Section 2.1.2 limits RCS pressure to less than 2750 psia. LCOs

22
Q

Why aren’t CEDMs removed?

A

CEDM housings are part of pressure boundary. Only operating coils are outside. Latches and other moving parts are inside the housing which is seal-welded (Omega) to dome.

23
Q

What are the Fission Product Barriers?

A
  • Cladding
  • RCS
  • Containment
24
Q

Unit 2 Lift setting of the Pzr Code Safeties is found to be 2498psig. Any T/S impact?

A

No T/S impact because all within 1% - Code safeties – TS 3.4.10

25
Q

Given: Unit 2, Heatup is underway, Tc=250F, Pzr pressure 1300psia
Given: Unit 1, Heatup in progress, Tc =191ºF, Tcet=192ºF, Press=1406psia, HU Rate= 11ºF /15mins
Any T/S impact?

A

Not meeting T.S. 3.4.9 per Fig 3.4-2 for heatups Apply action to restore within 30min - P/T limits – TS 3.4.9.1[3.9.1] Heat up & CD limits max CD to mode 5 is 100F/hr (more restrictive admin limits will also apply)

26
Q

Chemistry – TS 3.4.7 Given: Unit 1, 300psia, C/D in progress, Tc= 230F, Th= 231F, Cl .1ppm, Fluoride .16ppm, DO 1.19ppm. Any T/S impact?

A

No actions required

27
Q

Given: Unit 2, 300psia, C/D in progress, Tc= 100F, Th= 101F, Both SG Press. 200psig. Any T/S impact?

A

No actions required. T.S. 3.4.7 LCO is met. (Not Steady State, O2 limit N/A if < 250F.

28
Q

Why are the P/T curves different for each unit?

A

Variation due to Operating history and results of surveillance testing

Block 2 (8 decks)

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