Secondary startup neutron source

Abstract

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

Claims

1. A secondary startup neutron source comprising an enclosure having an ampule therein, the ampule having a housing wherein the antimony and beryllium are contained in a coaxial arrangement with the antimony in a central enclosure located in a central portion of the ampule, and the beryllium is in powdered form located in an annular space between the housing and the central enclosure.

2. The secondary startup neutron source according to claim 1, wherein the housing of the ampule is made of an alloy, which does not interact with antimony during filling and operation.

3. The secondary startup neutron source according to claim 2, wherein the housing of the ampule is made of a niobium-based alloy.

4. The secondary startup neutron source according to claim 2, wherein the housing of the ampule is made of a material weakly interactive with beryllium.

5. The secondary startup neutron source according to claim 4, wherein the ampule enclosure is made of ferritic-martensitic steel.

6. The secondary startup neutron source according to claim 1, wherein the powdered beryllium has a particle size from 60 to 200 micron, and a porosity of 45%.

7. The secondary startup neutron source according to claim 1, wherein the ampule is installed in the enclosure of the secondary startup neutron source with a 0.1 mm clearance.

8. The secondary startup neutron source according to claim 1, wherein the enclosure further comprises an upper gas collector above the ampule.

9. The secondary startup neutron source according to claim 1, further comprising an upper gas collector, wherein the upper gas collector is pressed against the ampule through washers by a spring.

10. The secondary startup neutron source according to claim 1, wherein at the ampule is located above a reflector and a lower gas collector within the enclosure.

11. The secondary startup neutron source according to claim 1, wherein an inner cavity of the enclosure is filled with helium.

12. The secondary startup neutron source according to claim 1, wherein the enclosure is leak-proof.

13. The secondary startup neutron source according to claim 12, wherein the enclosure is sealed with an upper shank and a lower shank.

14. The secondary startup neutron source according to claim 12, wherein the enclosure is sealed by argon-arc welding.

15. The secondary startup neutron source according to claim 1, wherein the enclosure has four spaced apart spiral ribs.

16. The secondary startup neutron source according to claim 1, further comprising a gas collector, a reflector, washers and a spring, and wherein the enclosure, gas collector, spring, reflector and washers are made of ferritic-martensitic steel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows the Secondary Startup Neutron Source in cross-section along a length thereof.

(2) FIG. 2 shows a cross-section of the ampule of the Secondary Startup Neutron Source.

(3) FIG. 3 shows a cross sectional view at A-A of FIG. 1.

EMBODIMENT OF THE INVENTION

(4) The container-type Secondary Startup operational neutron source has an enclosure 1 made of ferritic martensitic grade steel with a diameter of 12 mm in the smooth part, and the wall thickness of 0.4 mm, with four spiral ribs 13 shown in FIGS. 1 and 3 located on the outer side of the enclosure. The diameter along the ribs 13 is 13.5 mm, the rib winding pitch is 750 mm.

(5) 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.

(6) 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.

(7) At the bottom, the ampule is supported by a reflector 8 and a bottom gas collector 9.

(8) The neutron source enclosure inner cavity is filled with helium to ensure heat transfer.

(9) The neutron source enclosure is sealed with two shanks: upper shank 2 and lower shank 3.

(10) It is sealed by argon arc welding.

(11) The source enclosure, gas collectors, reflector and washers are made of martensite-ferrite grade steel.

(12) 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 14 (shown in FIG. 3) 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%.

(13) The ampule enclosure 12 is made of martensite-ferrite steel poorly reacting with beryllium.

(14) 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.

(15) 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.

(16) 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).