Survey of thermonuclear-reactor parameters.

Persiani, P.J.; Lipinski, W.C.; Hatch, Albert J.

doi:10.2172/4527550

“…5; (3) graphite is employed for neutron moderation; and (4) the neutron leakage from the blanket is relatively low, ~4% of the source neutrons. These characteristics are similar to those of several blanket models under current investigation [4], and therefore, the cross-section sensitivity exhibited by the blanket model of this paper is representative of a large class of blanket models. The cross-section sensitivity of tritium-breeding calculations in other classes of blanket 2 models will be examined in subsequent papers.…”

Section: Introductionsupporting

confidence: 77%

“…2% because of slightly reduced downscattering competition. 4 3. The changes in T 6 are accompanied by an ~ 19% change in the number of (n, 2n) reactions and an ~4% change in the number of niobium absorptions.…”

Section: The Secondary-neutron Energy Distributionmentioning

confidence: 99%

Mikhail Shlyomovich Birman (on his 70th birthday)

Buslaev¹,

2000

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The authors have examined the cross-section sensitivity of the tritium-breeding ratio in a fusion reactor blanket model which is representative of a large class of blanket configurations under current investigation. This blanket model exhibits the following tritium-breeding and neutronic characteristics: (1) liquid lithium of natural isotopic abundance is used for breeding; (2) the tritium-breeding ratio is in the "high" range, ~ 1. 5; (3) graphite is employed for neutron moderation; and (4) the neutron leakage from the blanket is relatively low, ~4% of the source neutrons. The sensitivity of the breeding ratio was evaluated by altering reference cross-section sets to reflect estimates of the uncertainties in the cross-section of the 6 Li(n,a)t, the 7 Li(n,n'a)t, and the 93 Nb(n,2n) reactions. Our analysis leads to the following observations:

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“…Table XIV shows that the effects on T 6 are fairly uniform in space. 4 Although the total non-elastic cross-section remains unchanged (the (n,2n) cross-section was reduced and the (n, n") cross-section was increased), the downscattering effectiveness is reduced because the (n, n') reaction is less effective in degrading the neutron energy than is the (n,2n) reaction.…”

Section: The Secondary-neutron Energy Distributionmentioning

confidence: 99%

Cross-section sensitivity of tritium breeding in a fusion reactor blanket: effects of uncertainties in cross-sections of ⁶Li, ⁷Li, and ⁹³Nb

Steiner¹,

Tobias²

1974

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The authors have examined the cross-section sensitivity of the tritium-breeding ratio in a fusion reactor blanket model which is representative of a large class of blanket configurations under current investigation. This blanket model exhibits the following tritium-breeding and neutronic characteristics: (1) liquid lithium of natural isotopic abundance is used for breeding; (2) the tritium-breeding ratio is in the “high” range, ∼ 1. 5; (3) graphite is employed for neutron moderation; and (4) the neutron leakage from the blanket is relatively low, ∼4% of the source neutrons. The sensitivity of the breeding ratio was evaluated by altering reference cross-section sets to reflect estimates of the uncertainties in the cross-section of the 6Li(n, α)t, the 7Li(n, n′α)t, and the 93Nb(n,2n) reactions. Our analysis leads to the following observations: The status of the 6Li(n,α)t cross-section data appears adequate for accurate (of the order of ∼1%) tritium-breeding calculations. We emphasize that this observation applies to the class of blanket configurations considered here and that other classes must be examined to determine the generality of the observation. Uncertainties in the cross-section and secondary-neutron energy distribution of the 7Li(n, n′α)t reaction attach uncertainties in excess of 5% to the tritium-breeding ratio. A re-evaluation of the relevant data in the energy range above ∼ 10 MeV might provide a smaller uncertainty, and we recommend that such a re-evaluation be undertaken. Additional measurements may be required to reduce the uncertainty in the tritium-breeding ratio to the order of 1 to 2%. Uncertainties in the (n, 2n) cross-section of 93Nb attach uncertainties of ∼ 2.4% to the tritium-breeding ratio. New experimental data on the 93Nb(n, 2n) cross-section are available, and a recent evaluation of this data suggests that the variations adopted here may reflect too pessimistic an estimate of the uncertainty. This point will be pursued in future studies When the cross-sections of the 6Li(n, α)t, the 7Li(n, n′α) t, and the 93Nb(n, 2n) reactions are varied simultaneously, the calculated uncertainty in the tritium-breeding ratio is ∼ 7 to 8%. This uncertainty approaches 10% when uncertainties in the secondary-neutron energy distribution of the 7Li(n, n′α)t reaction are included.

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The nuclear performance of vanadium as a structural material infusion reactor blankets

Steiner

¹

1974

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The nuclear performance of vanadium as a structural material in a deuterium-tritium fusion reactor is discussed. For comparison, calculations are also presented for niobium. The areas considered include: (1) tritium breeding; (2) nuclear heating; (3) radiation effects relating to material damage; and (4) neutron-induced activity. It is concluded that: (1) the tritium breeding characteristics of vanadium are somewhat superior to those of niobium; (2) nuclear heating in the first wall of the blanket will be substantially lower with vanadium than with niobium; (3) helium and hydrogen production in the first wall will be significantly greater with vanadium than with niobium; and (4) vanadium will exhibit an afterheat and biological hazard several orders of magnitude lower than that of niobium for times-after-shutdown of ∼ 100 days and greater.

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Survey of thermonuclear-reactor parameters.

Cited by 5 publications

References 4 publications

Mikhail Shlyomovich Birman (on his 70th birthday)

Mikhail Shlyomovich Birman (on his 70th birthday)

Cross-section sensitivity of tritium breeding in a fusion reactor blanket: effects of uncertainties in cross-sections of ⁶Li, ⁷Li, and ⁹³Nb

The nuclear performance of vanadium as a structural material infusion reactor blankets

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Survey of thermonuclear-reactor parameters.

Cited by 5 publications

References 4 publications

Mikhail Shlyomovich Birman (on his 70th birthday)

Mikhail Shlyomovich Birman (on his 70th birthday)

Cross-section sensitivity of tritium breeding in a fusion reactor blanket: effects of uncertainties in cross-sections of 6Li, 7Li, and 93Nb

The nuclear performance of vanadium as a structural material infusion reactor blankets

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Product

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Cross-section sensitivity of tritium breeding in a fusion reactor blanket: effects of uncertainties in cross-sections of ⁶Li, ⁷Li, and ⁹³Nb