WO2021139020A1

WO2021139020A1 - Multi-parameter detection system and method for intra-drill-hole nuclear facility decommissioning waste radioactivity

Info

Publication number: WO2021139020A1
Application number: PCT/CN2020/084540
Authority: WO
Inventors: 刘志毅; 刘军涛; 钱湘萍; 罗旭佳
Original assignee: 兰州大学
Priority date: 2020-01-12
Filing date: 2020-04-13
Publication date: 2021-07-15
Also published as: CN111175803B; CN111175803A

Abstract

Provided are a multi-parameter detection system and method for intra-drill-hole nuclear facility decommissioning waste radioactivity, relating to the field of source term surveys in the process of nuclear facility decommissioning. The system comprises a computer (1), a front-end machine, an array detection unit and a connection unit (5). The array detection unit comprises a position-sensitive scintillator detector unit (2), an independent semiconductor detection array unit (3) and a semiconductor detector and position-sensitive detector hybrid detection unit (4), wherein the position-sensitive scintillator detector unit (2), the independent semiconductor detection array unit (3) and the semiconductor detector and position-sensitive detector hybrid detection unit (4) all comprise a communication collection module, and the communication collection module is used for signal pre-amplification, formation, collection, and communication with the front-end machine; the position-sensitive scintillator detector unit (2) further comprises a position-sensitive scintillator detector; the independent semiconductor detection array unit (3) further comprises a semiconductor detector array; and the semiconductor detector and position-sensitive detector hybrid detection unit (4) further comprises a position-sensitive scintillator detector and a semiconductor detector.

Description

Radioactive multi-parameter detection system and method for decommissioned waste of drilling core facility

Technical field

The invention relates to the field of source item investigation in the decommissioning process of nuclear facilities, and in particular to a multi-parameter detection system and method for radioactive waste from decommissioning of borehole kernel facilities.

Background technique

The decommissioning of nuclear facilities is a very important part of the efficient and safe use of nuclear science and technology. The design, construction, operation and decommissioning of nuclear and radiation facilities is an inevitable law.

Source item investigation and monitoring is one of the important parts throughout the entire decommissioning process of nuclear facilities. It is not only the basis for project approval, but also the guarantee for high-efficiency, safe, and low-cost decommissioning, and it is also an important basis for completion acceptance. The complexity of the source item in the decommissioning of nuclear facilities is very high, and its cost needs to be implemented through the development of an optimized and scientific plan to achieve the goal of cost saving. Large nuclear facilities, such as nuclear power reactors, mainly use bulk concrete as the shielding material, and have been irradiated to varying degrees during the operation of nuclear facilities and have a certain degree of radioactivity. In the decommissioning process, according to the purpose of waste minimization, bulk concrete as the main radioactive waste greatly affects the technical plan and cost of decommissioning. Therefore, the accurate source item investigation of bulk concrete has important practical significance. However, the current solution is to obtain samples of different depths of concrete through drilling and send them to off-site laboratories for measurement and evaluation. The disadvantages are high cost, long cycle, off-site measurement, labor-intensive, and lack of real-time performance.

In addition, in the process of decommissioning nuclear facilities on site, it is first necessary to measure the residual radioactive pollution in the nuclear facilities to minimize the amount of radioactive waste to be managed. At present, the types and activities of radionuclides in wastes such as concrete at the decommissioning site of nuclear facilities are mainly used for radioactivity measurement and identification of the types of radionuclides with high-resolution HPGe detectors. The main problem is that the measured activity value is the comprehensive contribution value of the entire target object (such as concrete) to be measured. The inability to conduct continuous and deep radioactivity monitoring inside large-scale shielding materials such as concrete is contrary to the principle of minimizing the amount of radioactive waste. Normally, near the reactor core (or other radioactive sources), the radioactivity of the activated nuclides in the concrete is greater; while the concrete activated nuclides far away from the core (or other radioactive sources) The radioactivity is low. If the existing technology is used to measure only a comprehensive contribution limit, it is not conducive to the classification and treatment of the activity level of concrete waste, which increases the amount of radioactive waste to be processed, thereby significantly increasing the cost of decommissioning nuclear facilities.

Summary of the invention

The purpose of the present invention is to address the above-mentioned shortcomings and propose a multi-parameter detection system for decommissioning waste radioactivity in a hole core facility that provides guidance for the classification and treatment of radioactive waste through continuous deep radioactivity measurement inside large-scale nuclear decommissioning facilities such as concrete. method.

The present invention specifically adopts the following technical solutions:

A multi-parameter detection system for decommissioning waste radioactivity in a drilling core facility, including a computer, a front-end machine, an array detection unit and a connection unit. The array detection unit includes a position-sensitive scintillator detector unit, an independent semiconductor detection array unit, a semiconductor detector and a position Sensitive detector hybrid detection unit, position-sensitive scintillator detector unit, independent semiconductor detection array unit, semiconductor detector and position-sensitive detector hybrid detection unit all include communication acquisition modules, which are used for signal pre-amplification, shaping, and acquisition , Communication with front-end computer;

The sensitive scintillator detector unit also includes a position-sensitive scintillator detector. The position-sensitive scintillator detector evaluates the radioactivity in the borehole by measuring gamma ray counting;

The independent semiconductor detection array unit also includes a semiconductor detector array. The semiconductor detector performs nuclide discrimination by measuring the gamma ray energy spectrum, and measures alpha and beta rays to evaluate the nuclides that do not release gamma rays during the decay process;

The hybrid detection unit of the semiconductor detector and the position-sensitive detector includes a position-sensitive scintillator detector and a semiconductor detector. The position-sensitive scintillator detector evaluates the radioactivity in the borehole by measuring the gamma ray count, and measures the alpha, Beta rays evaluate the nuclides that do not emit gamma rays during the decay process.

A multi-parameter detection method for radioactivity of decommissioned waste from a borehole core facility adopts the above-mentioned multi-parameter detection system for radioactivity of decommissioned waste from a borehole core facility, which specifically includes the following steps:

a. Use drilling tools to drill large blocks of concrete in the decommissioning scenario of nuclear facilities;

b. Insert the multi-parameter detection system for the radioactivity of the decommissioned waste from the borehole core into the borehole obtained by drilling;

c. Calibrate the instrument before measurement. In the acquisition software, the radioactivity of the corresponding position of the radioactive scale sleeve moving in the axial direction of the detector array can be monitored. The radioactive scale sleeve contains several types below the exempt level. Standard radioactive source;

d. Connect power and signal lines to collect on-site measurement data;

e. Perform on-site raw data preprocessing and analysis based on the embedded data processing algorithm;

d. Give the activity measurement result and the identification type of nuclide.

The present invention has the following beneficial effects:

Through this system and method, continuous deep radioactivity measurement and nuclide screening inside large concrete bodies are realized, and reference data is provided for the classification and treatment of radioactive waste and reducing the amount of radioactive waste.

Description of the drawings

Figure 1 is a schematic diagram of a multi-parameter detection system for decommissioning waste radioactivity in a borehole core facility;

In Figure 1, 1 is a computer, 2 is a front-end machine, 3 is a gamma ray, 4 is a connection unit, 5 is a detector array unit, 6 is a drilling hole, and 7 is a bulk concrete body with decommissioning;

Figure 2 is a schematic diagram of the three types of detection units of the multi-parameter detection system for decommissioning waste radioactivity of the borehole core facility;

In Figure 2, 1 is a communication acquisition module, 2 is a position-sensitive scintillator detector, 3 is an independent semiconductor detector array, and 4 is a hybrid array of semiconductor detectors and position-sensitive scintillator detectors;

Figure 3 is a schematic diagram of the calibration of the multi-parameter radioactive detection system for decommissioned waste from drilling core facilities;

In Figure 3, 1 is a computer, 2 is a front-end machine, 3 is an instrument holder, 4 is a scale sleeve of a radioactive source, 5 is a connecting unit, and 6 is a detector array subunit.

Figure 4 is a schematic diagram of a multi-parameter detection method for radioactive waste from decommissioned waste from drilling core facilities;

Figure 5 shows the alpha energy spectrum data of continuous depth radioactivity monitoring inside a large concrete block.

Detailed ways

The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

A radioactive multi-parameter detection system for decommissioned waste from drilling core facilities, including a computer, a front-end machine, an array detection unit (mainly including gamma, Alpha, and Beta particle detection units) and a connection unit. The array detection unit includes a position-sensitive scintillator detector Unit, independent semiconductor detection array unit, mixed detection unit of semiconductor detector and position sensitive detector, as shown in Figure 2, position sensitive scintillator detector unit, independent semiconductor detection array unit, mixed detection of semiconductor detector and position sensitive detector The units all include a communication acquisition module, which is used for signal pre-amplification, shaping, acquisition and communication with the front-end computer;

The hybrid detection unit of the semiconductor detector and the position-sensitive detector includes a position-sensitive scintillator detector and a semiconductor detector 4. The position-sensitive scintillator detector evaluates the radioactivity in the borehole by measuring the gamma ray count and measures the alpha at the same time. , Beta rays evaluate the nuclides that do not emit gamma rays during the decay process.

a. Use drilling tools to drill large blocks of concrete in the decommissioning scenario of nuclear facilities. The diameter of the hole can be less than 5cm, which reduces the difficulty of drilling;

b. Insert the multi-parameter detection system for the radioactivity of the borehole core decommissioned waste into the borehole obtained by drilling, as shown in Figure 1;

c. Calibrate the instrument before measurement. In the acquisition software, the radioactivity of the corresponding position of the radioactive scale sleeve moving in the axial direction of the detector array can be monitored. The radioactive scale sleeve contains several exempt standard radioactive sources. Such as Am-241 (alpha source), Co-60 (gamma source), etc., as shown in Figure 3;

d. Connect power and signal lines to collect on-site measurement data;

d. Give the activity measurement result and the type of nuclide identification, the specific steps are shown in Figure 4;

Figure 5 shows the alpha energy spectrum of different internal depth points measured after a large concrete hole is drilled. By measuring the characteristic energy analysis of alpha particles, the nuclide identification of different internal depth points can be obtained. In this example, the different depth points are obtained. The types of nuclides are shown in Table 1.

Table 1

It can be seen from Table 1 that the present invention can well realize the continuous deep radionuclide identification inside the nuclear decommissioned bulk concrete, and provide important technical support for the classification and treatment of the later radioactive concrete and the minimization of radioactive waste.

Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the essential scope of the present invention shall also belong to the present invention. The scope of protection of the invention.

Claims

A multi-parameter detection system for decommissioning waste radioactivity in a drilling core facility, which is characterized in that it includes a computer, a front-end computer, an array detection unit and a connection unit. The array detection unit includes a position-sensitive scintillator detector unit, an independent semiconductor detection array unit, and a semiconductor Detector and position-sensitive detector mixed detection unit, position-sensitive scintillator detector unit, independent semiconductor detection array unit, semiconductor detector and position-sensitive detector mixed detection unit include communication acquisition module, communication acquisition module for signal pre-amplification , Forming, collecting, and communicating with the front-end computer;

The sensitive scintillator detector unit also includes a position-sensitive scintillator detector. The position-sensitive scintillator detector evaluates the radioactivity in the borehole by measuring gamma ray counting;

The independent semiconductor detection array unit also includes a semiconductor detector array. The semiconductor detector performs nuclide discrimination by measuring the gamma ray energy spectrum, and measures alpha and beta rays to evaluate the nuclides that do not release gamma rays during the decay process;

The hybrid detection unit of the semiconductor detector and the position-sensitive detector includes a position-sensitive scintillator detector and a semiconductor detector. The position-sensitive scintillator detector evaluates the radioactivity in the borehole by measuring the gamma ray count, and measures the alpha, Beta rays evaluate the nuclides that do not emit gamma rays during the decay process.
A multi-parameter detection method for radioactivity of decommissioned waste from a borehole core facility, characterized in that the multi-parameter detection system for radioactivity of decommissioned waste from a borehole core facility as claimed in claim 1, specifically includes the following steps:

a. Use drilling tools to drill large blocks of concrete in the decommissioning scene of nuclear facilities;

b. Insert the multi-parameter detection system for the radioactivity of the decommissioned waste from the borehole core into the borehole obtained by the above drilling;

c. Calibrate the instrument before measurement. In the acquisition software, the radioactivity of the corresponding position of the radioactive scale sleeve moving in the axial direction of the detector array can be monitored. The radioactive scale sleeve contains several types below the exempt level. Standard radioactive source;

d. Connect power and signal lines to collect on-site measurement data;

e. Perform on-site raw data preprocessing and analysis based on the embedded data processing algorithm;

d. Give the activity measurement result and the identification type of nuclide.