From High to Low Enriched Uranium Fuel in Research Reactors

Abstract

Since the 1970's, global efforts have been going on to replace the high-enriched (>90% 235U), low-density UAlx research reactor fuel with high-density, low enriched (<20% 235U) replacements. This search is driven by the attempt to reduce the civil use of high-enriched material because of proliferation risks and terrorist threats. American initiatives, such as the Global Threat Reduction Initiative (GTRI) and the Reduced Enrichment for Research and Test Reactors (RERTR) program have triggered the development of reliable low-enriched fuel types for these reactors, which can replace the high enriched ones without loss of performance. Most success has presently been obtained with U3Si2 dispersion fuel, which is currently used in many research reactors in the world. However, efforts to search for a replacement with even higher density, which will also allow the conversion of some high flux research reactors that currently cannot change to U3Si2 (eg. BR2 in Belgium), have continued and are for the moment mainly directed towards the U(Mo) alloy fuel (7-10 w% Mo). This paper provides an overview of the past efforts and presents the current status of the U(Mo) development.

Pore growth in U-Mo/Al dispersion fuel

“…At ANL, USA, the addition of a small amount of silicon to the Al matrix was proposed, and proven effective in inhibiting IL growth to some extent by subsequent in-pile and out-of-pile tests (see references in [7] [8]). At SCK-CEN, Belgium, a method of coating the U-Mo particles with either a ZrN-or Si-layer as a diffusion barrier was tested, and considerable success was also demonstrated [9]- [11]. At about the same time, KAERI, Korea, tried coating the U-Mo particles with either a UN-or a Si-layer, which also showed some effectiveness inhibiting IL formation [12].…”

STUDI KRITIKALITAS REAKTOR RISET DAYA RENDAH BERBAHAN BAKAR U3Si2Al

“…Data teknis perangkat bahan bakar dan perangkat bahan bakar-kendali yang digunakan dalam perhitungan kekritisan disajikan pada Tabel 1. Dalam studi kekritisan digunakan program MCNP di mana telah banyak diguanakan dalam analisis atau desain teras reaktor (8,9,10,11,12) . Dari hasil studi diharapkan dapat digunakan sebagai bahan pertimbangan dan kajian analisis keselamatan teras reaktor untuk pengganti teras TRIGA atau yang layak untuk dibangun jika akan membangun reaktor riset baru.…”

“…Untuk kondisi penyerap di dalam teras dengan faktor perlipatan neutron efektif 0,70794 berarti tingkat subkritiknya sangat tinggi, berarti tingkat keselamatan kondisi shutdown tinggi juga ( jauh dari kondisi kecelakaan kritis saat penyerap di dalam teras reaktor). Bahan bakar U3Si2-Al pengayaan rendah telah digunakan diberbagai Negara yang mengkonversi bahan bakar dari pengkayaan tinggi ke pengkayaan rendah (9,10,11) .…”

Irradiation behavior study of U–Mo/Al dispersion fuel with high energy Xe

“…Therefore, applying a protective layer on the fuel particle surface was proposed to eliminate the interaction between the U-Mo particle and the Al matrix [24,25]. ZrN is chosen as a suitable coating material, because it is metallurgically inert towards both the U-Mo particle and the Al matrix [25][26][27]. In this out-of-pile experiment, U-Mo/Al dispersion fuel samples fabricated with uncoated U-Mo powder or ZrN-coated U-Mo powder were irradiated.…”