Radiation Processing Plants Research Articles

STUDY OF FAST ELECTRON IRRADIATION EFFECT ON THE STRUCTURE AND SURFACE OF POLYAMIDE/ POLYETHYLENE/ETHYLENE VINYL ACETATE FILM MATERIAL USING THE UELR 10-10-40 PLANT

Radiation effect on the PA/PE/Eva film material with a thickness of 55 μm was investigated at theBurnazyanCenterusing radiation processing plant (RPP) with the UELR‑10–10–40 accelerator at 10 MeV. Polymer films were irradiated with doses of 0 to 18 kGy. The study of IR spectra showed that when processing the PA/PE/Eva film with fast electrons with a dose of up to 18 kGy using the UELR10–10–40 plant with a power of 10 MeV the number of functional -CH3 and -NHgroups in the IR spectra changes to 0.0060 relative units with radiation doses of 12 to 18 kGy, which leads to degradation of the sample and its crosslinking simultaneously. Using confocal laser microscopy, it was demonstrated that after irradiation of PA/PE/Eva sample with doses of 18 kGy, the surface of the film becomes smooth in РА layer and in Eva layer, and a spot thinning of the sample occurs. These characteristics may cause a change in the barrier properties of the film material and affect the shelf life of food in a packaging.

Radiation Processing: An Emerging Preservation Technique for Meat and Meat Products

<p>Development of shelf stable meat and meat products is a challenging task due to physico-chemical, microbiological and sensory alterations during storage. Lot of thrust is being given in the application of radiation processing in meat sector due to its microbial safety. Maintaining and delivering quality and safety products both in civilian and service sectors is the need of the hour. Even though irradiation can ensure complete microbial sterility it can lead to lipid and protein oxidation due to the formation of free radicals which can cause flavour changes. Several studies on the usage of natural antioxidants which can arrest these changes have been reported. Irradiation can find excellent applications in the extension of shelf life of chilled and non chilled carcasses and birds in service sectors. There are several radiation processing plants in India commissioned in the private sector which can also be utilized by Armed forces for extending the shelf life of whole carcass and birds with an extension of shelf life. This will be of great<strong> </strong>significance to the defence forces.</p><p><strong> </strong></p>

Study on the response of the ferrous ammonium sulfate - cupric sulfate dosimetry system of different salt concentrations at gamma chambers and radiation processing plant

Background and Aim: Gamma radiation is commercially used in food preservation by extending shelf life and the success of radiation preservation of food depends upon the ability of the processor of successful measurement of the radiation dose delivered to the foods. Several dosimeters are already used in radiation processing plant to measure the delivered dose. The aim of the present study was to develop a simple and appropriate chemical dosimetry system covering a wide dose range (1-30kGy) of food irradiation. Materials and Methods: The response of the ferrous ammonium sulfate (Fe(NH 4 ) 2 (SO 4 ) 2 ,6H 2 O) - cupric sulfate (CuSO 4 ,5H 2 O) dosimetry system was studied at two different gamma chambers of GC-5000 and GC-900 and at a radiation processing plant with four different salt concentrations and at the dose range of 1-30kGy. Results and Discussion: The system with highest salt concentration i.e. with 6x0.001mmol Fe(NH 4 ) 2 (SO 4 ) 2 ,6H 2 O + 6x0.01mmol CuSO 4 ,5H 2 O showed linear response in the applied dose range of 1kGy to 30kGy. Good reproducibility of the system was observed at both GC-5000 and GC-900 with different dose rate and irradiation temperature. Routine dosimetry and dose mapping at radiation processing plant with the standard Ceric-cerous dosimetry system with same salt concentration also showed good agreement with ΁5% difference. The system was stable upto 7 days before and after irradiation at 4 o C and at darkness. The estimated overall precision for the dose assessment over the dose range of interest was about ΁2% irrespective of the dose rate and irradiation temperature. Conclusion: The ferrous ammonium sulfate (Fe(NH 4 ) 2 (SO 4 ) 2 ,6H 2 O) - cupric sulfate (CuSO 4 ,5H 2 O) dosimetry system with highest salt concentration i.e. with 6x0.001mmol Fe(NH 4 ) 2 (SO 4 ) 2 ,6H 2 O + 6x0.01mmol CuSO 4 ,5H 2 O can be successfully used as chemical dosimeters in the dose range of 1-30kGy.

MONTE CARLO SIMULATION OF VARIOUS SOURCE-PRODUCT GEOMETRIES FOR A PROPOSED MULTI-PRODUCT GAMMA IRRADIATOR FACILITY

Radiation processing plants are designed to deliver a prescribed dose to product materials within the acceptable uniformity to meet the national standards. The dose uniformity ratios for four different product geometries of a proposed 37 PBq (10(6) Ci) 60Co-based, multi-product irradiator facility in India are evaluated using the Monte Carlo method for various product densities, 0.15 g cm-3, 0.4 g cm-3, and 0.6 g cm-3. The calculations are also carried out using the point kernel method for comparison purposes. The agreement between Monte Carlo and point kernel methods is within 3 to 15%. The suitable product geometry is identified based on dose uniformity ratios.

Estimation of DUR and source utilization efficiency for changing product dimensions and source activities in gamma irradiator

This paper discusses the application of the developed analytical method (Reji George, Jain, Pradhan, A.S., 2008. Theoretical evaluation of dose distribution in product in radiation processing plants. Radiat. Phys. Chem. 77, 186–191), for determining the activity loading pattern in a radiation processing plant to get the desired dose uniformity ratio (DUR) for processing mangoes and how the method was used to evaluate the expected source utilization efficiency for the redesigned source–product configuration.

Theoretical evaluation of dose distribution in product in radiation processing plants

An analytical method has been developed for the computation of dose rates at any number of points in the product material in a radiation processing plant in which radioactive source pencils are arranged in a rectangular vertical frame. Exposures from each individual source pencil and the movement of the product box was taken into consideration for the evaluation of absorbed dose. The validity of the computational method was tested for one of the existing irradiator already in operation. Excellent agreement was achieved between the computation and measured values of doses received by the product material. The method was then applied in the design of a new irradiator and was found very useful to arrive at optimum source size and target size. Hence, this method is being adopted for the design of all forthcoming 60Co irradiation plants in India.

Implementation of new IAEA isotope transport regulations

In the drive for continuous improvement in safety and control, the international regulations which govern the shipment of radioactive materials are being extended and updated. This will have an effect on the way in which Co-60 is transported to and from radiation processing plants. The nature of the regulatory changes is explored in this paper and the effect on users is discussed

Dosimetry procedures for an industrial irradiation plant

Accurate and reliable dosimetry procedures constitute a very important part of process control and quality assurance at a radiation processing plant. γ-Dose measurements were made on the GBS 84 irradiator for food and other products on pallets or in containers. Chemical dosimeters wre exposed in the facility under conditions of the typical plant operation. The choice of the dosimeter systems employed was based on the experience in chemical dosimetry gained over several years. Dose uniformity information was obtained in air, spices, bulbs, feeds, cosmetics, plastics and surgical goods. Most products currently irradiated require dose uniformity which can be efficiently provided by pallet or box irradiators like GBS 84. The radiation performance characteristics and some dosimetry procedures are discussed.

Section 9.2 process control: Comparison of guidelines for validation and routine monitoring of radiation processing plants

Recent published and draft guidelines on validation and routine monitoring of radiation processing plants are reviewed in the light of the proposed Single European Market.

Dose assurance in radiation processing plants

Radiation processing relies to a large extent on dosimetry as control of proper operation. This applies in particular to radiation sterilization of medical products and food treatment, but also during development of any other process. The assurance that proper dosimetry is performed at the radiation processing plant can be obtained through the mediation of an international organization, and the IAEA is now implementing a dose assurance service for industrial radiation processing.

Graphite calorimeter for absorbed dose standardization of γ-radiation processing plants

A four element graphite calorimeter consisting of a cylindrical absorber, jacket, mantle and shield was developed for direct measurement of absorbed dose at the centre of a 30 cm diameter and 30 cm height graphite phantom irradiated to 60Co γ-radiation in a radiation processing plant. The accuracy of the absorbed dose to graphite was estimated to be ±0.8% at a dose level of 40 × 10 −2 Gy s −1 (40 rad/s). The thermal kinetics of the calorimeter have been investigated.

The broad base of radiation processing using cobalt-60 in the United States

Only recently, an integrated, highly interdependent radiation processing industry based on the use of cobalt-60 has become established in the United States. The principal participants include nearly all the suppliers of disposable medical supplies, several major chemical companies, several privately owned corporations of modest size, the Crown Corporation of a foreign government, and several hundred firms which purchase radiation processing service. The total investment in radiation processing plant and equipment is on the order of fifty million dollars, and the annual retail value of products processed is in the many hundreds of millions of dollars. In all there are twenty-six process irradiators operating in fourteen different states, utilizing nearly twenty million Curies of cobalt-60. Sixteen of these systems are owned and operated by companies which process their own products more or less exclusively. The other ten are owned and operated by six different contract processors who produce and sell little if any product of their own manufacture. The successful efforts of the industry to develop new products and processes are supplemented by the activities of dozens of corporate, government and university research and test facilities located throughout the country. Several firms have designed and constructed viable radiation processing plants, and among the operating medical supply irradiators, there are four different types of conveying mechanism that have proven to be viable. There are two established suppliers of cobalt-60 sources in the megacurie range. Based upon the number of new plants that have been announced, ordered and are under construction, the base appears to be growing at the rate of about 20 percent per year, and many of the existing plants are experiencing increased utilization.

A lyoluminescence dosimetry system useful for high-dose intercomparison studies

Lyoluminescence dosimetry using glutamine is applicable in the dose range from 0.5–20 kGy (50 krad-2 Mrad) and thus of importance for radiation processing plants. The influence of storage conditions will be described.