Gamma source three-source combined full view exposure method for macrotype spherical storage tank

Abstract

The invention relates to a panoramic exposure method with three-source Gamma source combination of a large-scale spherical storage tank, which adopts the irradiation with three-source bound combination, can obtain a basically even panoramic radiation field, completely satisfies the standard fog density and sensitivity requirements of photographic plates, has greatly shortened irradiation time and novel techniques, is simple, convenient, safe, reliable and environment-protective, and can improve the nondestructive examination quality. The panoramic exposure method comprises the following technical steps: a central point of the spherical storage tank is obtained by measurement, a Gamma source head is packed on a nylon belt and positioned at the central point of the spherical storage tank, and the nylon belt is fixed in centers of an upper inlet orifice and a lower inlet orifice and strung by an euphroe, thus avoiding swinging; a source tank is connected with a drive device, and source transmission pipes and a drive hose are straightly positioned with the bend radius no less than the least Phi 500; the three source transmission pipes are bound together, and under the precondition that the geometric unsharpness is ensured, three irradiation heads turn outward in a petal shape so as to reduce mutual influence, increase irradiation area and reduce fade zone.

Description

1. Technical field: [0001] The invention relates to a non-destructive testing method for spherical tanks, in particular to a combined panoramic exposure method of gamma sources and three sources for large spherical tanks. 2. Background technology: [0002] In the background art, with the development and utilization of natural gas, a large volume (5000m 3 ~10000m 3 ) is increasing in number of spherical tanks. According to the management requirements of special equipment, non-destructive testing is an indispensable task when the spherical tank is manufactured and regularly inspected and controlled during its in-service period. The filming method will directly affect the manufacturing cost and regular inspection and maintenance of the spherical tank. cost. Today, domestic non-destructive testing companies generally use X-ray, ordinary industrial iridium source single source and special industrial iridium source single source (source intensity ≥ 250Ci) three methods when tes...

AI Technical Summary

Problems solved by technology

For the panoramic exposure process, we generally use Ir192 single-source central transillumination. Due to the limitation of the surface leakage of the storage source equipment, the general maximum limit is only 100Ci

With the extension of time, the source intensity attenuation is often less than 100Ci when used

However, practice has proved that when the filming time is longer than 18 hours, the fog of the negative film will increase significantly, the sensitivity will seriously decrease, and the exposure effect will not meet the evaluation requirements.

In addition, long-term exposure will increase the impact of radioactive sources on the surrounding environment, and the corresponding safety costs will increase significantly.

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