Basic Specifications -Monju Plant -

Reactor type Fast breeder reactor
Cooling System Sodium cooled (loop-type)
Thermal output 714 MW
Electrical output 280 MW
Fuel Plutonium-Uranium mixed oxide
Core Dimensions:  
............. Equivalent diameter 180 cm (approx.)
............. Height 93 cm
............. Volume 2340 litres
Plutonium enrichment ( % Pu fiss.) Inner / Outer 16 / 21
Fuel Mass:  
............. Core ( U+Pu metal ) 5.9 t
............. Blanket ( U metal ) 17.5 t
Average burn-up 80 000 MWd/t (approx.)
Cladding tube dimensions
.... Outer diameter / thickness
6.5 mm / 0.47 mm
Cladding tube material SUS 316
Power density 275 kW / litre
Blanket thickness
.... Upper / lower / radial
30 / 35 / 30 cm
Breeding ratio 1.2 approx.
Primary sodium temperature
.... Reactor inlet / outlet
397° / 529°C
Secondary sodium temperature
.... IHX inlet / outlet
325° / 505°C
Number of loops 3
Reactor vessel dimensions
.... Height / diameter
18 / 7 m
Steam Pressure
.... Before main stop valve
127 kg/cm2
Interval between refuelling 6 months (approx.)
Refuelling system Single rotating plug with fixed arm fuel handling machine

 

Overview
Reactor

Reactor Vessel

Reactor Vessel

Operating pressure:  
............. At reactor vessel inlet 8 kg/cm2 G
............. At reactor vessel outlet 1 kg/cm2 G
Operating temperature:  
............. At reactor vessel inlet 397°C
............. At reactor vessel outlet 529°C
Dimensions:  
............. Inner diameter 7.1 m (approx.)
............. Height 17.8 m (approx.)
............. Thickness 50 mm
Material SUS 304

 

Overview
Reactor Core

Reactor Core Loading

Reactor Core Loading                     
detail
Core fuel assemblies ....
Inner core / outer core
108 / 90
Radial breeder blanket assemblies 172
Control rods ....
Fine / Coarse / Back-up
3 / 10 / 6
Neutron source 2
Neutron shield assembly 316
Surveillance assembly 8

 

Overview
Core Internals

Core Internal Structure

Core Internal Structure

Core internal support structure .... Outer diameter / height 6.3 / 1.7 m (approx.)
Core support plate diameter 3.7 m (approx.)
Core barrel .... Outer diameter / height 4.0 / 3.5 m
Inner barrel .... Outer diameter / height 6.6 / 5.87 m
Main material SUS 304

Reactor Top Shield Plug

Type Single rotating plug
Dimensions:  
.... Max. diameter of the fixed plug 9.5 m
.... Height of the fixed plug 7.5 m
.... Max. diameter of the rotating plug 5.9 m
.... Thickness of the rotating plug 2.8 m
Main material SUS 304 / Carbon Steel
Sealing system Low melting point alloy / Artificial rubber (back-up)
Max. speed of rotating plug 0.1 rpm

 

Overview
Above Core Structure

Above Core Structure

Above Core Structure

Shield part .... Outer diameter / height 2.6 / 2.7 m
Connecting cylinder ....
Outer diameter / height
2.1 / 5.1 m
Flow controller .... Max. diameter 2.0 m (approx.)
Main material SUS 304

 

Overview
Primary Sodium Pump

Primary Sodium Pump

Primary Sodium Pump

Number of pumps 3 ( one per loop)
Capacity .... Main motor / pony motor 5100 / 600 tonnes per hour
Head 92 mNa
Max. operating pressure ....
Outlet side / suction side
10 / 2 kg cm-2 G
Max. operating temperature 420° C
Main material SUS 304
Main motor .... Power / speed 2000 kW / 837 rpm
Pony motor .... Power / speed 22 kW / 167 rpm

 

Overview
IHX

Intermediate Heat Exchanger

Intermediate Heat Exchanger ( IHX )

Type Vertical parallel flow with no sodium surface
Number of units 3 ( one per loop )
Capacity 238 MW
Coolant flow rates ....
Primary / secondary
5100 / 3700 tonnes per hour
Operating temperatures:  
.... Primary inlet 529°C
.... Primary outlet 397°C
.... Secondary inlet 325°C
.... Secondary outlet 505°C
Number of tubes 3294
Outer diameter of tube 21.7 mm
Thickness of tube 1.2 mm
Outer diameter of cylinder 3 m
Height 12.1 m
Main material ( Cylinder & tubes ) SUS 304

 

Overview
Evaporator


Overview
Superheater

Steam Generator

Steam Generator

  Evaporator Superheater
Type Helical coil
( once through )
.... as Evaporator
Number 3 ( one per loop ) .... as Evaporator
Sodium flow rate 3700 tonnes per hour .... as Evaporator
Water / steam flow rate 380 tonnes per hour .... as Evaporator
Operating temperatures:
( at rated power )
   
.... Sodium inlet 469°C 505°C
.... Sodium outlet 325°C 469°C
....Water inlet 240°C -------
.... Steam inlet ------- 367°C
.... Steam outlet 369°C 487°C
Heat transfer tubes:    
.... Number 140 147
.... Outer diameter 31.8 mm 31.8 mm
.... Thickness 3.8 mm 3.5 mm
Shell diameter 3 m 3 m
Shell height 15.23 m 11.8 m
Main materials:    
.... Cylinder 2.1/4Cr-1Mo Alloy SUS 304
.... Tubes 2.1/4Cr-1Mo Alloy SUS 321

 

Overview
Turbine

Steam Turbine

Steam Turbine

Type Tandem, 3 cylinder, 4 flow exhaust, non-reheat
Number 1
Rated power 280 MW
Rotation speed 3600 rpm
Steam pressure before main stop valve 127 kg/cm2
Steam temperature before main stop valve 483°C
Steam mass into turbine 1100 tonnes per hour
Condenser vacuum 722 mmHg
Number of rows of blades ....
High pressure / low pressure
8 / 6 (4 flows)
Length of low pressure turbine last blade 0.58 m

 

Overview
Fuel Handling Machine

Fuel Handling Machine

Fuel Handling Machine

Type Fixed arm type
Number 1
Capacity 1 core assembly
Rotating radius 1.67 m
Main body .... Length / vertical stroke 14.2 m / 4.6 m
Main material SUS 304

 

Overview
EVST

Ex-Vessel Fuel Storage Tank

Ex-Vessel Fuel Storage Tank

Type Sodium filled tank containing rotating rack
Number 1
Capacity 250
Main material SUS 304
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