Scalable Production of Lead-212 and Actinium-225 Generators with Fusion Neutrons
Abstract
Targeted alpha therapy will require a large expansion of 212Pb and 225Ac production. We propose neutron- and photon-driven routes that convert 230Th, 231Pa, 232Th, and 237Np into generator parents 228Th and 229Th. The most direct 225Ac route is 230Th(n,2n)229Th. A 10 MW deuterium-tritium (D-T) neutron source irradiating thorium with a 27% 230Th isotopic fraction accumulates about 250 Ci of 229Th in six months, initially enough for five million 225Ac dose-equivalents per year, and its 7916 yr half-life makes it useful for millennia. This requires only ∼2 gigawatt-days of D-T fusion operations. Thermal-neutron irradiation of tens of grams of 230Th produces gram quantities of 232U, a decades-long source of 228Th for millions of 212Pb dose-equivalents per year. Alternate routes proceed through 231Pa: fusion neutrons produce 1 to 2 tonnes of 231Pa per gigawatt-year from 232Th, and a thermal reactor converts up to 0.4 g of 232U per gram of 231Pa. Each gram of stored 232U produces 10 mg (8.2 Ci) of 228Th per year. Subsequent 228Th(n,γ)229Th converts 0.07 to 0.34 g of 229Th per gram of 228Th. We also analyze the 237Np(n,2n)236mNp route to 228Th. These pathways scale from kilowatt to megawatt D-T sources and could secure millions of 212Pb and 225Ac dose-equivalents per year.
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BibTeX
@misc{parisi2026scalable,
title = {{Scalable Production of Lead-212 and Actinium-225 Generators with Fusion Neutrons}},
author = {J. F. Parisi and A. Rutkowski},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.19166},
eprint = {2609.19166},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.19166},
}
RIS
TY - UNPB
TI - Scalable Production of Lead-212 and Actinium-225 Generators with Fusion Neutrons
AU - J. F. Parisi
AU - A. Rutkowski
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.19166
UR - https://arxiv.org/abs/2609.19166
AB - Targeted alpha therapy will require a large expansion of ^212Pb and ^225Ac production. We propose neutron- and photon-driven routes that convert ^230Th, ^231Pa, ^232Th, and ^237Np into generator parents ^228Th and ^229Th. The most direct ^225Ac route is ^230Th(n,2n)^229Th. A 10 MW deuterium-tritium (D-T) neutron source irradiating thorium with a 27% ^230Th isotopic fraction accumulates about 250 Ci of ^229Th in six months, initially enough for five million ^225Ac dose-equivalents per year, and its 7916 yr half-life makes it useful for millennia. This requires only ∼2 gigawatt-days of D-T fusion operations. Thermal-neutron irradiation of tens of grams of ^230Th produces gram quantities of ^232U, a decades-long source of ^228Th for millions of ^212Pb dose-equivalents per year. Alternate routes proceed through ^231Pa: fusion neutrons produce 1 to 2 tonnes of ^231Pa per gigawatt-year from ^232Th, and a thermal reactor converts up to 0.4 g of ^232U per gram of ^231Pa. Each gram of stored ^232U produces 10 mg (8.2 Ci) of ^228Th per year. Subsequent ^228Th(n,γ)^229Th converts 0.07 to 0.34 g of ^229Th per gram of ^228Th. We also analyze the ^237Np(n,2n)^236mNp route to ^228Th. These pathways scale from kilowatt to megawatt D-T sources and could secure millions of ^212Pb and ^225Ac dose-equivalents per year.
ER -