201.03 Rx Vessel & Internals Flashcards Preview

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Flashcards in 201.03 Rx Vessel & Internals Deck (36):
1

201.03 Rx Vessesl & Internals


Approx. dimensions of Rx Vessel

42.6' high x 14.4 wide (i.d)

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201.03 Rx Vessesl & Internals


Materials used to make Rx Vessel & Internals

Manganese Molybnenum

with

304 SS Clad approx. 5/32"

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201.03 Rx Vessesl & Internals


Nozzle Dimensions

Inlet - 27.5 "

Outlet - 29"

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201.03 Rx Vessesl & Internals


How is the vessel supported?

Two hot legs and two cold legs are supported within primary shield wall on support shoes

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201.03 Rx Vessesl & Internals


How is the head bolted?

Roto-lock head bolts use lugs instead of conventional threads to engage flange and attach stud tensioner. Conventional threads for nut.

Liberal clearances, no galling

Quick installation of stud tensioners

Time spent in Vicinity of Vessel is reduced by a factor of six

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201.03 Rx Vessesl & Internals


How is the head sealed?

Two hollow, pressurized o-rings with two drain lines (1 outside, 1 inbetween). Common temp switch warns of leakage at 20 F above ambient

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201.03 Rx Vessesl & Internals


What are the head penetrations used for?

58 in lower head - incore NIs

67 in upper head

57 - CRDMs

4 - CETs

3 - internals disconnect device

2 - RVWL instrumentation

1 - Head Vent

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201.03 Rx Vessesl & Internals


Purpose of vessel specimens

Metal specimens from same batch as vessel are placed between core barrel and vessel wall. Periodically tested to ensure vessel embrittlement is as expected.

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201.03 Rx Vessesl & Internals


Head and Vessel Alignment Pins

Four Manganese Molybdenum pins keep head aligned during assembly

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201.03 Rx Vessesl & Internals


Core Barrel

Two-section welded SS cylinder accommodates fuel assemblies

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201.03 Rx Vessesl & Internals


Radial Support

6 inconel keys on core support forging fit into 6 keyways welded around periphery of vessel to provide radial support and alignment

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201.03 Rx Vessesl & Internals


Thermal Shield

304 SS pad reduces gamma heating and neutron embrittlement of the vessel

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201.03 Rx Vessesl & Internals


Lower Core Support Plate

20" SS forged plate supports weight of fuel assemblies and directs uniform flow through the core

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201.03 Rx Vessesl & Internals


Baffle and Former

SS, bolted to circular core barrel to transition to squared off core periphery

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201.03 Rx Vessesl & Internals


Instrument Thimble Guides

SS, guide and support incore NIs

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201.03 Rx Vessesl & Internals


Secondary Support Assembly

SS, limits stress on lower head if internals dropped from core barrel or flange failure

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201.03 Rx Vessesl & Internals


Upper Support Assembly

SS, provides axial support for upper core plate and support columns

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201.03 Rx Vessesl & Internals


Internal Support Ledge

supports all weight of reactor internals and core

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201.03 Rx Vessesl & Internals


Support Columns

50 SS columns establish spacing for upper core plate and support assembly

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201.03 Rx Vessesl & Internals


Control Rod Guide Tubes

Sheath and guide RCCAs and drive shaft

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201.03 Rx Vessesl & Internals


Upper Core Plate

Radial support to RCCA guide tubes and fuel assemblies

Directs flow from fuel assemblies to outlet plenum

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201.03 Rx Vessesl & Internals


Fuel Enrichment & Location Pattern

varied for even power distribution (flatter flux profile) and fuel burnup

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201.03 Rx Vessesl & Internals


Fuel Assembly

Bottom nozzle

box-like structure that distributes flow through the assembly

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201.03 Rx Vessesl & Internals


Fuel Assembly

Top Nozzle

Protects rodlets from coolant cross-flow

Directs flow through upper core plate

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201.03 Rx Vessesl & Internals


Fuel Assembly

Hold Down Springs

4 springs per assembly provide hold down force

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201.03 Rx Vessesl & Internals


Fuel Assembly

Rod Guide Thimbles and Dash Pot

Provide guide channels for control rods. Lower 39" smaller diameter to provide hydraulic cushion for dropped rod

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201.03 Rx Vessesl & Internals


Fuel Assembly

Grid Assembly

10 per assembly for lateral support and proper rodlet positioning. Mixing vanes stick out into coolant flow to cause turbulent flow and insrease heat transfer.

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201.03 Rx Vessesl & Internals


Fuel Assembly

Incore Detector Thimbles

Located in center of each fuel assembly for incore instrument guide tubes

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201.03 Rx Vessesl & Internals


Fuel Assembly

Fuel Rods

Zirc 4 tubing plugged and seal welded to encapsulate fuel pellets

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201.03 Rx Vessesl & Internals


Fuel Assembly

Fuel Pellet

Uranium Dioxide with dished ends to allow axial expansion

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201.03 Rx Vessesl & Internals


Burnable Poison Rods

Not currently used.

integral Fuel Burnable Absorbers (IFBAs) consiting of B-10 coatings on fuel pellets in selected fuel rods currently used

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201.03 Rx Vessesl & Internals


Secondary Sources

Antimony-Beryllium regenerative sources located in locations H-3 and H-13 provide detectable neutron levels while shutdown

 

A image thumb
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201.03 Rx Vessesl & Internals


Rod Control Cluster Assembly

57 RCCAs with 24 rodlets each

Silver - Indium - Cadmium

held in proper positions for insertion or withdrawl by spider assembly

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201.03 Rx Vessesl & Internals


RVWL

Heated junction thermocouple assemblies sense temp difference as water covers sensor. 2 channels of 8 sensors:

2 in upper head - 100% and 64%

Plenum - 100%

Top of Hot Leg - 85%

Middle of Hot Leg - 66%

Bottom of Hot Leg - 48%

b/w bottom of Hot Leg and Upper Core Alignment Plate - 33%

just above Upper Core Alignment Plate - 20% 

 

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RVWL Operability and operation

A channel is OPERABLE if four or more sensors, one or more in upper section and three or more in lower section, are OPERABLE.

Minimum of 1 OPERABLE channel

Displays on QDPS and ICS

>200 F delta between heated an unheated indicates uncovered

<25 F - shorted, > 2300 F - open

 

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201.03 Rx Vessesl & Internals


Core Bypass Flows

8.5 % total bypass flow:

2.5% through bypass nozzles cool Rx Vessel Head

2.0% through thimbles with RCCAs cool control rods

2.0% through thimble guide tubes with no RCCAs, sources, poisons, or thimble plugs

1.0% between cold and hot leg nozzles

0.5% between baffle wall and core barrel

0.5% between fuel and baffle wall