Environmental Engineering Reference
In-Depth Information
Table 1.1
Reactor types and characteristics
Parameter
PWR
VVER
BWR
RBMK
Coolant
Pressurized
water
Pressurized
water
Boiling
water
Boiling
water
Average power
rating (kW/L)
80-125
83/108
40-57
5
Fast neutron fl ux
average (n/cm
2.
s)
6-9
×
10
13
5
×
10
13
/7
×
10
13
4-7
×
10
13
1-2
×
10
13
Temperature (°C)
320-350
335-352
285-305
290
Table 1.2
Components, requirements and possible candidate materials
Component
Requirements
Possible materials
Moderators and
refl ectors
Low neutron absorption
Large energy loss by neutron
per collision
High neutron scattering
Water - H
2
O, D
2
O
Beryllium - BeO
Graphite - C
Control
materials
High neutron absorption
Adequate strength
Low mass (for rapid
movement)
Corrosion resistance
Stability under heat and
radiation
Boron - B
Cadmium - Cd
Hafnium - Hf
Rare earths - Eu, Gd, Dy, etc.
Coolants
Low neutron absorption
Good heat-transfer properties
Low pumping power (Low T
M
)
Stability under heat and
radiation
Low induced radioactivity
Non-corrosiveness
Gases - Air, H
2
, He, CO
2
, H
2
O
Water - H
2
O, D
2
O
Liquid Metals - Na, NaK, Bi
Molten Salts (-Cl, -OH, -F)
Organic Liquids
Shielding
materials
Capacity to slow down
neutrons
Absorption of gamma
radiation
Absorb neutrons
Light water - H
2
O
Concrete, Most control
materials
Metals - Fe, Pb, Bi, TA, W,
Boral - B and Al alloy
Structural
materials
Low neutron absorption
Stability under heat and
radiation
Mechanical strength
Corrosion resistance
Good heat-transfer properties
Al, Be, Mg, Zr
Ferritic Steels
Stainless Steels
Superalloys (Ni based)
Refractory metals - Mo, Nb,
Ti, W, etc.
criteria are based on physical, mechanical, thermal and nuclear characteris-
tics including the chemical and nuclear stability as well as the resistance to
radiation damage and induced radioactivity. Table 1.2 summarizes the various
components and major requirements along with possible materials. Based on
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