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Nuclide
Table 4. Nuclide concentration and radiation characteristics of
tungsten target irradiated by external neutrons from blanket
Initial
concentrations
T = 1 yr
T = 0.5 yr
Φ = 10 14 cm -2 s -1 Φ = 10 15 cm -2 s -1
180
W 0.126-2 9.6-4 1.3-3
181
W 0 1.2-4 6.6-6
182
W 0.263 0.26 0.26
183
W 0.143 0.14 0.14
184
W 0.306 0.31 0.31
185
W 0 6.0-4 7.1-5
186
W 0.286 0.28 0.28
187
W 0 3.1-5 2.4-5
188
W 0 2.9-5 2.0-7
182
Ta 0 1.1-5 4.0-9
183
Ta 0 3.5-7 3.6-10
186
Re 0 7.8-6 6.7-8
188
Re 0 2.3-6 3.5-7
Q, Ci/g – 32.4 18.1
RT, litre/g – 1.7 + 9 8.5 + 7
QΓ, (R cm 2 /g hr) – 5.5 + 4 4.1 + 4
Nuclide
Table 5. Nuclide concentrations and radiation characteristics
of a tungsten target irradiated by 10 MeV neutrons
Initial
concentrations
T = 1 yr
T = 0.5 yr
ϕ = 10 15 cm -2 s -1 ϕ = 10 16 cm -2 s -1
180
W 1.3-3 1.4-3 2.6-3
181
W 0 4.2-3 0.030
182
W 0.263 0.26 0.25
183
W 0.143 0.15 0.17
184
W 0.306 0.29 0.24
185
W 0 4.0-3 0.03
186
W 0.286 0.27 0.22
187
W 0 3.0-8 2.5-7
182
Ta 0 1.0-7 1.9-6
186
Re 0 3.2-7 1.0-6
188
Re 0 4.7-12 2.0-10
Q, Ci/g – 62.2 486
RT, litre/g – 5.1 + 9 4.1 + 10
QΓ (R cm 2 /g hr) – 3.9 + 3 9.9 + 4
In low energy irradiation, self-blocking effects are very high. For this reason, production of new
nuclides is low in purely thermal spectrum even in high flux 10 13 cm -2 s -1 . For neutron spectrum typical
for light water blanket, with γ = 0.4, nuclide production is higher because of epithermal neutrons.
Radiotoxicity at γ = 0.4 is determined by all radioactive nuclides. At γ = 0, 185 W gives a major part to
radiotoxicity. Radiation doze power is determined by short-lived 188 W.
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