The use of sophisticated equipment in a radioactive environment necessitates an evaluation of radiation tolerance for all essential elements. Gamma irradiation facility must be carried out, ideally under realistic circumstances. Furthermore, the construction of new reactors and plant life extension programs for existing reactors enhance the requirement for testing and, as a result, the need for a gamma irradiation facility.
The gamma irradiation facilities have been extensively used for food irradiation studies, developing optimized radiation doses for medical product sterilization, and radiation effects evaluations on electronic components and other materials such as optical components (mirrors, lenses, and windows) for space applications. Radiation-induced cross-linked polymers have been the subject of biomedical research for medical applications such as tissue engineering and better prostheses. Other research focuses on the impact of radiation on polymers used in cancer therapy. Below are some of the gamma irradiation facilities for assessment
High-Dose Rate Facilities
This facility is an irradiation chamber with a 512 cubic foot equidimensional volume. There is a broad variety of dosage rates available, from 1 Gray (100 rad) per hour to 10,000 Gray (1 Mrad) per hour. Several tiny apertures pierce one shielding wall to provide instrumentation wires access. Bulk sterilization, bulk material assessment, and electronic component evaluation are all used.
Low-Dose Rate Facilities
Increased Sensitivity to Low Dose Rates
The Enhanced low dose rate sensitivity facility comprises four separate irradiation chambers that provide dose rates of less than 0.01 Rad/s (36 Rad/hr) and homogenous photon flux distribution. There are test cable penetrations and a vast space for test equipment. Higher dosage rates are available for this facility if necessary.
Uses of High-Dose Rate Facilities
Electronic Component Evaluation.
Intended initially for radioisotope sample processing, this building now contains a shielded irradiator. The irradiator can provide up to two gamma beams at dosage rates of 0.01 Rad/s. A remote-controlled overhead crane, remote robotic manipulators, a protected viewport, and numerous conduit ports are also available at the facility.
The field of photons from the calibrator has been extensively defined for dosimetry-related tests for high-energy photon calibration. It may be used to evaluate the reactions of ionizing radiation dosimeters and equipment to N-16 photons, which is very useful for nuclear plant worker safety. There are dose equivalent rates of up to 300 mrem/hr available.
A self-contained wet source storage irradiator is an irradiator in which the radioactive source is kept in a pool of water. The source is always shielded, and human access to the source and the volume being irradiated is physically limited in its intended configuration and appropriate mode of operation.
A controlled human access irradiator is a panoramic gamma irradiation facility. When not in use, the radioactive source is kept and thoroughly protected in a pool of water. The source is exposed inside a radiation chamber that is kept inaccessible during operation by a keypad entry system.
Before making any changes to the irradiator that may significantly affect radiation protection, the operating organization should get permission from the regulatory authority. The manufacturer(s) of gamma irradiation facilities and their suppliers and essential components should be consulted about planned irradiator changes.