Decommissioning methods

Based on these circumstances, JAPC has been executing the investigations and researches. Among these activities, Assessment of radioactive inventory and "Feasibility study of decommissioning method are described below. 

Decommissioning may be achieved in different ways, depending on the facilities type and the location. This section will also briefly look at the ways in which decommissioning can be deferred by extending the field life, and then at the main methods of well abandonment and facilities decommissioning. 

One or more of these methods may be necessary to achieve the desired decontamination levels, four of which are described in Table 2-1 of the Decontamination Report (Appendix 2) in the Decommissioning Plan (U.S. Army, 2000d). 

Scheuerer et al. [5] determined 63Ni in soils. The method is applicable to analytical measurements needed during the decommissioning of nuclear power plants. 

Gorigledzhan, E.A. (2001) Methods and procedures of ensuring environmental safety when dismantling nuclear submarines with damaged reactor compartments, in Proceedings of international conference Environmental Problems of Complex Decommissioning of Nuclear Submarines", Severodvinsk, pp. 71-75 (in Russian). 

Calculation method. When dealing with bays and estuaries wherein the decommissioned NS and RU are stored afloat, some exposure paths typical for open sea are unimportant. E.g., there is no ingestion intake for lack of sea fishery and nonuse of both the bay waters and coastal areas for recreational purposes. In such areas the following exposme paths are the most important [4] ... 

An assessment must be performed and documented to determine the most appropriate method for preserving archives. Selection of the appropriate method must be considered within the context of the size, complexity, scope, and business impact of the system to be decommissioned. The method chosen must be documented using the appropriate Change Control form. 

AN EFFICIENT AND OPTIMISED TOTAL COMBUSTION METHOD FOR TOTAL H-3 AND C-14 IN ENVIRONMENTAL AND DECOMMISSIONING SAMPLES... 

Radiochemical methods which allow sequential determination of radionuclides are often desirable for reasons of speed and cost-effectiveness, for example in mixed waste streams or in waste characterization for nuclear decommissioning. Although a variety of methods are in use for the analysis of in concretes, they tend to use large reagent volumes and involve... 

The most obvious application of this method is in waste characterisation associated with nuclear decommissioning, where activated concrete bioshields are a potential source of activity. A core from a bioshield has been analysed using gamma spectrometry, analysis and determination. The core used was too old for any " Ca to be detected, but... 

At this time, only space disposal can provide absolute protection for humanity, its descendants and the planet earth. New methods may be discovered in the future, but current planning should include the accounting for disposal of decommissioned reactor materials in space. Whatever method is selected, good initial planning will make the disposal of the old fusion reactors a safe, relatively easy, and cost effective process. 

In the past, incineration was the disposal method of choice for organochlorine compounds such as PCBs, 2,4,5-trichlorophenoxyacetic acid (245 T), ethylene dichloride (EDC) tar, and chlorinated pesticides. It was used in Europe between 1969 and 1994, with a total of some 350 burns, and in the Gulf of Mexico and the Pacific Ocean,for 13 research burns between 1975 and 1983 [169]. Between 1980 and 1985, an estimated 100,000 tonnes of waste were incinerated annually, mostly in the North Sea (IMO web site), and regulations related to incineration at sea were added to the London Dumping Convention. The issue has caused considerable controversy, with strong opinions for and against [170-173]. Because of the risks of spills or other accidents at sea, and according to the precautionary principle, it seems that the practice has been abandoned world-wide [174] and the last incineration vessel was decommissioned in February 1991 (IMO web site). 

Development of a method of visual surveillance of conditions of refractory, electrodes, and other units of the melter during its operation and after decommissioning. 

RAJAN, K.K., GURUMOORTHY, K., RAJAN, M., KALE, R.D., Sodium cleaning and disposal methods in experimental facilities, paper presented in the Technical Committee Meeting on Sodium Removal and Disposal from LMFRs in Normal Operation and in the Framework of Decommissioning, Aix-en-Provence, France, 1997. 

Processes approved for sodium treatment are water chemical methods. Alcohol is forbidden by the CEA since an accident occurred during the decommissioning of the RAPSODIE reactor in 1994 [7, 8], Physical cleaning methods (e.g. scraping, evaporation) are more limited at an industrial scale due to their relatively tedious nature. 

The start-up and operation of the Na-cooled fast reactors Phenix and Superphenix has provided a large amount of valuable experience, as the decommissioning of Superphenix is doing right now. We shall focus here on the feedback of the neutron physics experiments performed in both reactors on the neutron physics calculation tools and methods. 

AR132 Methods for the minimization of radioactive waste from decontamination and decommissioning of nuclear facilities. No. 401, 5 July 2001. 

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