Embrittlement is the primary factor limiting the lifetime of reactor pressure vessels (RPVs). This literature review provides an overview of the causes of hardening and non-hardening embrittlement in RPV steels, with a specific emphasis on precipitation hardening caused by manganese–nickel rich precipitates (MNPs) in thermally aged RPV steels. Several models used to describe the hardening mechanism are discussed. The role of atom probe tomography (APT) in investigating solute clustering in RPV steels is also discussed. The characterisation of nanoscale clusters is enabled by APT’s unique combination of high mass and 3D spatial resolution. This technique, its limitations and the relevant statistical analysis methods available are reviewed.

Understanding thermally induced embrittlement in low copper RPV steels utilising atom probe tomography

A study of predicting irradiation-induced transition temperature shift for RPV steels with XGBoost modeling

Annealing of a reactor pressure vessel embrittled by neutron irradiation constitutes the only known technique to restore the initial material properties, to an extent that depends on the annealing conditions and on the materials. This technique is used in WWER-440 type reactor pressure vessels. A very important related issue is the one of re-embrittlement behaviour of the material after the annealing. In this respect, there is an obvious link with radiation embrittlement understanding. This report compiles the vast amount of information on annealing and re-embrittlement, which is available in the European countries where such annealing operations have been performed. In addition this topic was also investigated in various TACIS-PHARE projects, and the conclusions are included here as well. To complete the state-of-the-art, the results from a number of annealing experiments carried out in US on “Western” type RPV steels have also been considered. How to obtain EU publications Our priced publications are available from EU Bookshop (http://bookshop.europa.eu), where you can place an order with the sales agent of your choice. The Publications Office has a worldwide network of sales agents. You can obtain their contact details by sending a fax to (352) 29 29-42758. The mission of the JRC is to provide customer-driven scientific and technical support for the conception, development, implementation and monitoring of EU policies. As a service of the European Commission, the JRC functions as a reference centre of science and technology for the Union. Close to the policy-making process, it serves the common interest of the Member States, while being independent of special interests, whether private or national.

Annealing and Re-embrittlement of Reactor Pressure Vessel Materials - State of the Art Report

The invention discloses an automatic regulating device for a detection probe of an electronic tension meter. The automatic regulating device comprises a pressure control mechanism, a telescoping mechanism, a height regulating mechanism and a fixing mechanism. Positioning sheets are installed at the blade portions of the electronic tension meter, permanent magnets are installed at the four corners of the bottom of a support, a rotation block is in threaded connection with a support rod and is locked through a nut above the rotation block and a nut below the rotation block, the telescoping mechanism is installed in the rotation block and is connected with the pressure control mechanism through a regulating rod, a piston rod of the pressure control mechanism is in threaded connection with the electronic tension meter, and the positioning sheets are installed at the blades of the electronic tension meter. According to the automatic regulating device, quick installing and clamping of the electronic tension meter are achieved, discharge operations are achieved, operation time is shortened, operation steps are simplified, the pressure between the blades of the electronic tension meter and linear materials can be accurately controlled, the surfaces of the materials are easily protected, friction force between the blades and the linear materials is guaranteed, and accuracy of test data is guaranteed. By the adoption of the automatic regulating device, less than 10 seconds is needed, and operation efficiency is greatly improved.

Automatic regulating device for detection probe of electronic tension meter

The invention belongs to the technical field of nuclear reactor fuel, and particularly relates to a test device for metal material creep under the in-reactor radiation environment. The test device comprises a thin-walled circular pipe, a mandrel, a first end plug and a second end plug, the first end plug and the second end plug are fixedly connected with the upper end and the lower end of the thin-walled circular pipe correspondingly, the mandrel is arranged in the thin-walled circular pipe, one end of the mandrel is fixedly connected with the first end plug, gaps exist between the other end of the mandrel and the thin-walled circular pipe as well as between the other end of the mandrel and the second end plug, and the thin-walled circular pipe is pre-filled with pressure inert gas. The test device is simple in structure, convenient to realize and feasible in manufacturing, and the demands of cladding material creep test research and data acquisition under the irradiation environment in a test reactor and a commercial reactor can be met.

Test device for metal material creep under in-reactor radiation environment

Irradiated for 4 cycles inside the reactor, the irradiation surveillance capsule (ISC) was withdrawn and transported to Nuclear Power Institute of China (NPIC) for dismantling in the hot cell. This paper presented tensile tests and Charpy-V impact tests on non-irradiated and irradiated specimens. Tensile tests were performed at room temperature and 300 °C respectively, and Charpy-V impact tests were performed at series temperatures. Instrumented impact curves and tensile curves were obtained and analyzed. Impact absorbed energy, lateral expansion and crystallinity transition curves were plotted by a hyperbolic tangent function. The irradiation-induced shift of transition temperature, upper shelf energy, tensile strength and yield strength were determined. And irradiation-embrittlement effect on RPV was evaluated by prediction and measurement of irradiation-induced transition temperature shift. Results showed that the parameters including neutron fluence and transition temperature were in normal range, and the next capsule could be withdrawn according to original irradiation monitoring program.Copyright © 2010 by ASME

Irradiation-Embrittlement of Reactor Pressure Vessel Steel

The utility model discloses a structure of an installing device of postdose fuel cladding pipe end plugs. The structure comprises an air cylinder, a fixing seat and a sample slot, which are connected in sequence, wherein an ejector rod is arranged between the air cylinder and the fixing seat; one end of the ejector rod is fixed on the air cylinder; the top end of the fixing seat is concave to form a fixing slot; an end plug box is arranged in the fixing slot; a spring piece and a plurality of end plugs which are arranged side by side are arranged in the end plug box, an ejector rod channel running through the fixing seat is arranged on the fixing seat; an end plug channel running through the end plug box is arranged in the end plug box; the central line of the ejector rod channel, the central line of the ejector rod, the central line of the end plug at the bottommost end, and the central line of the end plug channel are in the same straight line; and a pressing block is arranged on the sample slot. According to the structure, the condition that a fuel cladding pipe can not be damaged during the preparation of a fuel cladding pipe stretching sample is ensured, and the tightnesses of the prepared stretching sample end plugs are the same by selecting same air pressure during the preparation of the samples; and the structure has the advantages that the method is simple and convenient, the operation in a hot room can be facilitated, the cost is low, and the exposure dose on workers can be reduced.

Structure of installing device of postdose fuel cladding pipe end plugs

The utility model discloses an installation structure of a sample extensometer. The installation structure comprises screw rods, a base and fixing plates arranged at two ends of the base, wherein a groove concave inward is formed at the top end of the base, screw holes are symmetrically formed in the fixing plates and above the base, one side of each fixing plate far away from the base is provided with a round block, the center line of each round block is on the same straight line with the center line of each screw hole, the diameter of each round block is larger than the major diameter of each screw hole, and the screw rods penetrate through the corresponding round block and are connected with the screw hole in a screwed mode. The installation structure is simple in structure and convenient to operate. Installation and clamping of the sample extensometer is achieved after a manipulator smoothly finish irradiation, work staff do not need to contact irradiation samples in a short distance, irradiation dose of the work staff is effectively reduced, and safety of the work staff is protected.

Installation structure of sample extensometer

The utility model discloses a vertical arc metal specimen tensile test special fixture of postose small -size, including the anchor clamps main part, the anchor clamps main part includes the same cylindrical section of diameter and semicircle shell of column, cylindrical section one end and semicircle shell of column coaxial coupling, the other end is provided with the inside sunken internal thread coaxial with the cylindrical section, the side follow the diameter be provided with with the parallel cotter hole of semicircle shell of column diametral plane, be provided with the arc sample groove of undercut on the diametral plane of semicircle shell of column along the axis, the one end in arc sample groove links to each other with the cylindrical section, and the other end is provided witharc processes. The utility model discloses the anchor clamps main part is divided into cylindrical section and semicircle shell of column, sets up arc sample groove on the semicircle shell of columndiametral plane, makes the tensile sample atress more even in the tensile sample, and the tentation data is more accurate.

Vertical arc metal specimen tensile test special fixture of postose small -size

The invention discloses an irradiated internal pressure blasting sample sealing joint automatically sealing device. The irradiated internal pressure blasting sample sealing joint automatically sealingdevice solves the problems of long waiting time and low testing efficiency due to the fact that original testing can be implemented only when the dosage of a sample is attenuated to an acceptable range after a long period of time. The irradiated internal pressure blasting sample sealing joint automatically sealing device comprises a base, a support mounted on the base for mounting a fuel tube, agroove formed in the support for mounting a pressing cap of a tightening sleeve on the fuel tube, the tightening sleeve arranged on the base and coaxial to the groove for mounting a sealing joint, a rotating module for driving the tightening sleeve to rotate, and a linear driving module for driving the tightening sleeve to move linearly along the axis. The irradiated internal pressure blasting sample sealing joint automatically sealing device can be applied in a hot cell for testing without long-time attenuation of the dosage of the sample, thereby greatly improving the testing efficiency; meanwhile, an automatically disassembled locking joint is reusable and can reduce production of radioactive waste.

Zhang Haisheng

Papers

Irradiation-Embrittlement of Reactor Pressure Vessel Steel

Structure of installing device of postdose fuel cladding pipe end plugs

Installation structure of sample extensometer

Vertical arc metal specimen tensile test special fixture of postose small -size

Irradiated internal pressure blasting sample sealing joint automatically sealing device