Disposal of High-Level Nuclear Waste in Deep Horizontal Drillholes

Abstract

Spent nuclear fuel and high-level radioactive waste can be disposed in deep horizontal drillholes in sedimentary, metamorphic, or igneous rocks. Horizontal drillhole disposal has safety, operational, and economic benefits: The repository is deep in the brine-saturated zone far below aquifers in a reducing environment of formations that can be shown to have been isolated from the surface for millions of years; its depth provides safety against inadvertent intrusion, earth¬quakes, and near-surface perturbations; it can be placed close to the reactors and interim storage facilities, minimizing transportation; disposal costs per ton of waste can be kept substantially lower than for mined repositories by its smaller size, reduced infrastructure needs, and staged imple¬mentation; and, if desired, the waste could be retrieved using “fishing” technology. In the proposed disposal concept, corrosion-resistant canisters containing unmodified fuel assemblies from commercial reactors would be placed end-to-end in up to 50 cm diameter horizontal drill¬holes, a configuration that reduces mechanical stresses and keeps the temperatures below the boiling point of the brine. Other high-level wastes, such as capsules containing 137Cs and 90Sr, can be disposed in small-diameter drillholes. We provide an overview of this novel disposal concept and its technology, discuss some of its safety aspects, and compare it to mined repositories and the deep vertical borehole disposal concept.

Borehole RW Disposal Concept and Prospects of its Implementation in Russia

“…Успехи в технологии бурения нефтегазовых скважин, проникающих к углеводородным залежам по наклонной, вплоть до горизонтальной, траектории породили проекты удаления ОЯТ и ВАО в латеральные отрезки протяженных скважин . Проект ЛСЗ, подробно обоснованный в работе [11], нацелен на осадочные пласты на глубине около 1,5 км (рис . 4а) .…”

“…Различия связаны с глубиной размещения . Принцип обеспечения безопасности ЛСЗ повторяет принцип ГСЗ с опорой на геологическую среду в том, что стратификация солености, геохимия вод с низким редокс-потенциалом и пробки в скважине должны подавить вынос радионуклидов в биосферу [11] .…”

“…Концепция удаления долгоживущих РАО в ГСЗ также развивается в Австралии [10] и рассматривается в ряде других стран . В США, кроме того, в самые Захоронение РАО последние годы предложена концепция захоронения РАО в латеральных участках протяженных скважин, пройденных в глинистых породах осадочного чехла, залегающего на глубинах до 600-1500 м [11] .…”

Research on transport safety of spent fuel based on trend analysis

“…These are the severe trends currently faced by the transportation of spent fuel, which have attracted great attention from scholars at home and abroad. At present, the transportation problems of spent fuel that need to be solved urgently include the management and disposal of spent fuel transportation [3] . At the same time, benefiting from the rapid development of China's economy and the investment and construction of nuclear power facilities, nuclear power plants have been increased in accordance with national plans, especially in coastal cities.…”

Corrosion Performance of Engineered Barrier System in Deep Horizontal Drillholes

“…The disposal of spent nuclear fuel (SNF) and other high-level radioactive waste (HLW) in deep horizontal drillholes is an innovative system to meet the pressing national and international need for the safe and reliable disposal of nuclear waste [1,2]. Holes are vertically drilled one to three kilometers (several thousand feet) deep into or below a low-permeability geologic formation, then slowly turned nearly horizontal to create a disposal section that extends for up to three kilometers (nearly two miles) along the stratification of a suitable disposal formation.…”