SPECIAL REQUIREMENTS FOR FABRICATION OF PROCESS EQUIPMENT FOR RADIO-CHEMICAL PLANTS OF NUCLEAR FUEL CYCLE FACILITIES

摘要

Radio-chemical plants for various applications in nuclear fuel cycle facilities have been in existence for last many decades in India. They have complex nature of operations and problems associated with handling of large amount of radioactivity in dispersible forms.Jdost of the processes as carried out in radio-chemical plants use nitric acid based solutions. Highly oxidizing nature of nitric acid environment in such plants makes the equipment vulnerable to corrosion. In addition, equipment congestion, complex piping and high radiation fields in shielded cells pose challenges to carry out any contact maintenance. Accessing any equipment for maintenance or repair work inside the shielded cells needs massive decontamination efforts and high men-rem expenditure. Such maintenance work in process cells results into long shut-down of plants. It is imperative to have a high degree of reliability for the process equipment to minimize maintenance work. Hence, appropriate and stringent fabrication requirements are laid to enhance the confidence level on structural integrity of these critical process equipment. Many special requirements to safeguard against probable reasons of mechanical failures are identified in addition to fabrication requirements specified in various applicable codes and standards. These requirements are dictated by the importance given to the equipment for radiological safety in the plant. This paper summarizes the special requirements being practiced for the fabrication of such equipment employed in the nuclear fuel cycle facilities.