Operational Neutron Source

Abstract

The invention relates generally to nuclear engineering and more particularly to controlled reactor start-up. The invention improves reliability of an operational neutron source by creating additional safety barriers between the coolant and the source active part materials. The operational neutron source is designed as a steel enclosure housing an ampule containing antimony and beryllium with separate antimony and beryllium cavities positioned coaxially. The antimony is contained in the central enclosure made of a niobium-based alloy unreactive with antimony. A beryllium powder bed is located between the antimony enclosure and the ampule enclosure. The ampule enclosure is made of martensite-ferrite steel poorly reacting with beryllium. An upper gas collector is located above the ampule, which serves as a compensation volume collecting gaseous fission products. At the bottom, the ampule is supported by a reflector and a bottom gas collector. The gas collectors, reflector and washers are made of martensite-ferrite grade steel.

Claims

1. The operational neutron source containing an enclosure with active elements inside (antimony and beryllium isotopes), wherein the active elements are placed in an ampule of a coaxial design.

2. The operational neutron source according to claim 1, wherein antinomy is contained in the ampule central enclosure.

3. The operational neutron source according to claim 1, wherein beryllium is located between the ampule central enclosure and the ampule enclosure.

4. The operational neutron source according to claim 1, wherein the ampule central enclosure is made of an alloy which does not react with antimony during filling and operation.

5. The operational neutron source according to claim 4, wherein the ampule central enclosure is made of a niobium-based alloy.

6. The operational neutron source according to claim 1, wherein beryllium is a powder with particle size from 60 to 200 micron, and the beryllium powder bed porosity is 45%.

7. The operational neutron source according to claim 4, wherein the ampule enclosure is made of a material poorly reacting with beryllium.

8. The operational neutron source according to claim 7, wherein the ampule enclosure is made of martensite-ferrite grade steel.

9. The operational neutron source according to claim 1, wherein the ampule is installed in the neutron source enclosure with a 0.1 mm clearance.

10. The operational neutron source according to claim 1, wherein there is an upper gas collector above the ampule, which serves as a compensation volume collecting gaseous fission products.

11. The operational neutron source according to claim 1, wherein the gas collector is pressed against the ampule through washers with a spring.

12. The operational neutron source according to claim 1, wherein at the bottom, the ampule is supported by a reflector and a bottom gas collector.

13. The operational neutron source according to claim 1, wherein the neutron source enclosure inner cavity is filled with helium to ensure heat transfer.

14. The operational neutron source according to claim 1, wherein its enclosure is leak tight.

15. The operational neutron source according to claim 14, wherein the enclosure is sealed with two shanks: upper and lower ones.

16. The operational neutron source according to claim 14, wherein it is sealed by argon arc welding.

17. The operational neutron source according to claim 1, wherein its enclosure has four spiral ribs providing an additional safety barrier.

18. The operational neutron source according to claim 1, wherein the neutron source enclosure, gas collectors, reflector and washers are made of martensite-ferrite grade steel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 shows the operational neutron source cross-section, general view.

[0026] FIG. 2 shows the cross-section of the operational neutron source ampule.

EMBODIMENT OF THE INVENTION

[0027] The container-type operational neutron source has an enclosure 1 made of martensite-ferrite grade steel with a diameter of 12 mm in the smooth part, and the wall thickness of 0.4 mm, with four spiral ribs located on the outer side of the enclosure. The diameter along the ribs is 13.5 mm, the rib winding pitch is 750 mm. (Not shown in the drawing)

[0028] The enclosure houses an ampule 4 with active elements: antimony and beryllium. The active components are located in separate antimony and beryllium cavities of coaxial design.

[0029] An upper gas collector is located above the ampule 5, which serves as a compensation volume collecting gaseous fission products. The gas collector 5 is pressed against the ampule through washers 7 with a spring 6.

[0030] At the bottom, the ampule is supported by a reflector 8 and a bottom gas collector 9.

[0031] The neutron source enclosure inner cavity is filled with helium to ensure heat transfer.

[0032] The neutron source enclosure is sealed with two shanks: upper and lower ones 3.

[0033] It is sealed by argon arc welding.

[0034] The source enclosure, gas collectors, reflector and washers are made of martensite-ferrite grade steel.

[0035] FIG. 2 shows the ampule of a coaxial design with the antimony 10 in the ampule central enclosure 11. The ampule central enclosure 11 is made of a niobium-based alloy which does not react with antimony during filling and operation. A beryllium bed (not shown) is located between the ampule central enclosure 11 and the ampule enclosure 12. Beryllium is a powder with particle size from 60 to 200 micron, and the beryllium powder bed porosity is 45%.

[0036] The ampule enclosure 12 is made of martensite-ferrite steel poorly reacting with beryllium.

[0037] The central ampule enclosure containing the antimony is leak tight. The ampule central enclosure and its elements may be made, for example, of the VN-2AE alloy.

[0038] The ampule 4 is placed in the enclosure 1 of martensite-ferrite grade steel with a 0.1 mm clearance. The length of the ampule active part is 190 mm, the overall length of the operational neutron source (active part) is 1,720 mm.

[0039] Due to provision of additional safety barriers between the coolant and the source active part materials, the operational neutron source ofthe claimed design, its active part, provides reliable operation of the reactor plant for a campaign of 53,000 effective hours (approximately 8 years).