The status of storage of spent fuel from reactors: Bangladesh perspective

Full text: In Bangladesh, a 3 MW TRIGA MARK II research reactor is the main nuclear research facility in the country. The reactor has so far been operated for about 3428 hours with a total burn-up of about 5750 MWh. The reactor uses TRIGA LEU fuel with normal uranium content of 20% by weight. The enrichment level of the fuel is 19.7%. At the same time, Bangladesh Atomic Energy Commission (BAEC) is seriously pursuing a project to establish a 600 MW PWR type nuclear power plant in the west-central part of the country in near future. In regard to the safe management, storage and disposal of wastes from the present operation of the research reactor and the future operation of the power reactor, BAEC is going ahead with specific plans and program. Presently, there is not a single spent fuel element in the reactor facility and with the present trend of burn-up, it seems that BAEC TRIGA will not generate any spent fuel by the year 2009. BAEC TRIGA facility has three Fuel Storage Pits made of stainless located in the floor of the reactor hall. These pits are meant for temporary storage of spent fuel elements as well as radioactive samples. The storage pits were designed to hold 19 TRIGA fuel elements in each pit. The pit can be water filled to accommodate storage of irradiated fuel elements. There are also 3 fuel storage racks, each capable of holding 10 fuel elements, located along the walls of the reactor tank to provide temporary storage of fuel-moderator of graphite dummy elements. With regard to the management of the spent fuel from the proposed nuclear power plant, direct disposal after conditioning is envisaged rather than reprocessing. Water pool (wet) storage at the reactor site for a period of more than 30 years is being considered prior to the final disposal in a crystalline rock repository in the northern part of the country. A Central Waste Processing and Storage Facility (CWPSF) is fast nearing completion in the AERE, Savar campus. A national strategy exists for the management and disposal of various types of radioactive wastes including spent fuel. The authority for the control of all radiological and nuclear practices in Bangladesh is the Bangladesh Atomic Energy Commission (BAEC). The legal basis for this control are the 'Nuclear Safety and Radiation Control (NSRC) Act 1993 and the Nuclear Safety and the Radiation Control Rules, 1997' which essentially incorporate the requirements of the international Basic Safety Standards. The Act requires a license to carry out any radiological and nuclear practice in the country while the rules prescribe the conditions to be fulfilled and the manner by which a license has to be obtained. Disused spent sealed sources are being stored in an interim storage in the CWPSF following short treatment and conditioning. As to their disposal the currently preferred option is engineered repository. Site investigation has progressed towards establishing a demonstration repository at AERE, Savar by the year 2010. For long-lived highly active problem wastes including spent radium needles and disused radioactive sources, the safe management option is a longterm storage in the CWPSF following treatment and conditioning. But this is not considered as a sustainable solution. The real emphasis is placed on the development of inexpensive disposal methods and availing regional/international repositories. A long-term storage is not a sustainable solution because it has got its own type of risks and uncertainties associated with it. The ideal disposal option for highly active highly toxic 'problem waste' will be a regional or an international geological repository particularly for countries like Bangladesh which has small resource base. Spent fuel storage facilities may be situated at-reactor (RA) or outside the boundary of a nuclear power station, in other words, away-from-reactor (AFR), possibly at a centralized site. Such facilities may also be classified by the medium of storage, either in the form of 'wet' or 'dry' storage. Wet storage facilities for spent fuel are those facilities which involve the storage of spent fuel in water pools. The spent fuel may be supported within the pool by racks, and/or contained in canisters placed within the water medium. Dry storage facilities for spent fuel are those facilities which involve storage of spent fuel in a gas environment, such as an inert gas or air. Dry storage includes the storage of spent fuel in casks or vaults. A cask is a massive container which may or may not be transportable. Vaults consist of above or below-ground reinforced concrete buildings containing arrays of storage cavities suitable for the containment of one or more fuel units. Various types of wet and dry storage facilities are in operation or are under consideration in different countries. Spent fuel can be safely stored for long periods of time (some spent fuel has already been stored for over thirty years). The future nuclear power programme and the associated spent fuel management programme in the Peoples Republic Bangladesh is under review. An interim spent fuel storage facility will be set up to manage spent fuel safely and economically for many decades, thereby providing adequate time to develop an integrated spent fuel management system. The current major issues are to secure a site for the facility and to optimize the storage concept. Considering the delicate public acceptance issues and the pursuit of universally accepted methods for safe spent fuel management, close international co-operation is desirable to resolve the upcoming challenges. (author)