Caution Is Needed in Operating and Managing the Waste of New Pebble-Bed Nuclear Reactors

Abstract

Rainer Moormann studied physical chemistry in Braunschweig, Germany, obtaining his PhD in 1976. From 1976 to 2013 he worked at Research Center Juelich (FZJ) on the safety of pebble bed reactors, fusion reactors, and spallation sources. In 2011 he received the German Whistleblower Prize for publications on widely unknown problems and accidents in German pebble bed reactors.

A Limited-Scope Probabilistic Risk Assessment Study to Risk-Inform the Design of a Fuel Storage System for Spent Pebble-Filled Dry Casks

“…Additionally A canister is a cylindrical stainless-steel structure to accommodate spent fuel elements. In the case of HTR-PM, a canister is 1.74 m in diameter, 4.18 m in height, and 20 mm in thickness to store about 40,000 spent fuel pebbles [65]. Due to the thin thickness, the canister's radiation shielding is vulnerable.…”

"Advanced" isn't Always Better: Assessing the Safety, Security, and Environmental Impacts of Non-Light-Water Nuclear Reactors

“…Rainer Moormann, a German HTGR researcher who has become a leading skeptic of the technology, concludes that future pebble-bed HTGRs should include leak-tight containments, given the many unresolved safety issues including the potential for fuel temperatures and fission product releases to greatly exceed expected values (Moormann 2009). In a recent critique of the HTR-PM commercial demonstration pebble-bed reactor that is under construction in China, Moormann and collaborators proposed a number of safety upgrades to compensate for the absence of a leak-tight containment at the reactor, such as improving the confinement vent filtration system (Moormann, Kemp, and Li 2018). However, even such upgrades cannot provide the same level of safety assurance as a robust containment.…”

Numerical Study on the Thermal Field and Heat Transfer Characteristics of a Hexagonal-Close-Packed Pebble Bed

“…The spherical fuel elements in a high-temperature gas-cooled reactor (HTGR) core are randomly packed [1], resulting in uneven heat transfer on the surface of the pebbles and hotspots being formed [2], which will affect the integrity of the fuel spheres and may cause serious accidents [3,4]. The formation of local hotspots is closely related to the porosity [5][6][7], the diameter of the pebble [8][9][10], and the flow state of the coolant in the pebble bed [11,12].…”