Method for recovering plutonium from radioactive spent fuel

A spent fuel and radioactive technology, applied in recycling technology, plutonium compounds, climate sustainability, etc., can solve problems such as increased Pu generation, complex solvent reuse process, and increased total radioactivity, and achieve the effect of improving efficiency

Active Publication Date: 2017-06-27
CHINA INSTITUTE OF ATOMIC ENERGY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] 2. With the improvement of nuclear power economy, the fuel burnup of nuclear power plants is deepened, and the deepening of burnup will not only increase the total radioactivity in the Purex process, but also increase the amount of Pu generated, and the α specific activity of the Pu element is large The percentage of isotopes also increases accordingly; while the radioactive energy of α-rays can be completely absorbed by the solvent, multiple factors together aggravate the radiolysis of the solvent, and the impact of radiolysis products on plutonium stripping will be more serious
[0011] 2. The effluent organic phase contains U, which makes the solvent reuse process more complicated

Method used

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  • Method for recovering plutonium from radioactive spent fuel
  • Method for recovering plutonium from radioactive spent fuel
  • Method for recovering plutonium from radioactive spent fuel

Examples

Experimental program
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Effect test

Embodiment 1

[0030] Embodiment 1: the effect test of organic phase DMHAN reduction Pu (IV)

[0031] The 30% TBP / n-dodecane organic phase containing 1.02g / L Pu receives a radiation dose of 1.4Wh / L, and generates about 100mg / L of HDBP. The solution spectrum shows that Pu(IV) appears at 720nm and 740nm -Characteristic absorption peaks of HDBP complexes. Mix the above-mentioned Pu-containing organic phase with 30% TBP / n-dodecane organic phase containing 0.31mol / L DMHAN at a volume ratio of 1:1, and the brown Pu(IV) is reduced in less than 5 seconds into blue Pu(III). After 1 minute of mixing, the solution spectrogram shows that Pu(III) characteristic absorption peaks appear at 570nm and 605nm, and the Pu(IV) characteristic absorption peaks at 720nm and 740nm disappear, as figure 1 shown. From the changes in the spectra, it can be seen that even in the presence of HDBP, DMHAN in the organic phase can fully reduce Pu(IV).

[0032] For the above-mentioned TBP organic phase containing HDBP, if...

Embodiment 2

[0033] Embodiment 2: the test of supplementary stripping plutonium in the organic phase

[0034] A supplementary stripping test for plutonium in the organic phase is designed, the process is as follows figure 2 Shown:

[0035] (1) Back-extract most of Pu(IV) with dilute nitric acid aqueous solution containing DMHAN and MMH in the 2B tank, and reduce the concentration of nitric acid and nitrous acid in the organic phase at the same time to avoid DMHAN and Pu(IV) in the subsequent organic phase Since the plutonium concentration in the organic phase of each sample in the 2B tank is very low, the number of plutonium stripping stages in the 2B tank can be appropriately reduced;

[0036] (2) The organic phase after the stripping of the 2B tank containing a small amount of Pu (IV) enters the organic phase reaction tank, reacts with 30% TBP containing DMHAN, and the organic phase after the reaction contains Pu (III) and DMHAN, and flows into the 2BXX tank;

[0037](3) In the 2BXX t...

Embodiment 3

[0040] Embodiment 3: Effect comparison of different ways of recovering plutonium from the organic phase

[0041] Prepared plutonium-containing organic phase (29%TBP-1%HDBP-0.158g / LPu-0.250mol / L HNO 3 ), the plutonium was stripped in different ways, and the operating conditions and plutonium stripping effects are shown in Table 1. As can be seen from Table 1, since the amount of HDBP is much greater than the amount of plutonium, HAN is directly used to strip Pu in the organic phase (there is no organic phase reduction for Pu(IV), so Pu(IV) is reduced during direct stripping. ) is very slow) has almost no effect, and directly adopts DMHAN for plutonium stripping (the organic phase reduction of Pu(IV) is not carried out, so although the speed of reducing Pu(IV) in direct stripping is higher than that of HAN, it still cannot meet the requirements. Requirements) the effect is also very limited, the plutonium stripping method can obviously improve the stripping effect of plutonium ...

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Abstract

The invention belongs to the technical field of treatment of nuclear materials and relates to a method for recovering plutonium from a radioactive spent fuel. The method sequentially comprises the following steps: performing extraction: extracting tetravalent plutonium in an aqueous solution of the radioactive spent fuel with an organic solvent containing tributyl phosphate; performing reduction on plutonium with a reducing agent: adding an organic solvent containing dimethylhydroxylamine in an organic phase to reduce the tetravalent plutonium into trivalent plutonium; and performing back extraction: adding a dilute acid aqueous solution in the organic phase to perform back extraction on the plutonium into a water phase, and performing recovering. Through adoption of the method for recovering the plutonium from the radioactive spent fuel, disclosed by the invention, the efficiency of recovering the plutonium from the radioactive spent fuel can be obviously improved compared with HAN back extraction, and the problem caused by reduction and extraction with U (IV) can be solved at the same time.

Description

technical field [0001] The invention belongs to the technical field of nuclear material processing and relates to a method for recovering plutonium from spent radioactive fuel. Background technique [0002] The industrial-scale reprocessing of spent radioactive fuel has a history of more than 70 years. There are 17 countries engaged in reprocessing, among which Britain, France, Russia, India, Japan and other countries have successively built and operated commercial reprocessing plants, with rich experience Operating experience. my country began research on power reactor reprocessing technology in the 1970s. Since the beginning of the new century, with the further development of my country's nuclear power, the development of my country's reprocessing technology is gradually entering the fast lane, and the commissioning of the power reactor reprocessing pilot plant has been completed. A commercial reprocessing plant project is planned. [0003] In terms of the spent radioacti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B60/04C22B3/38C22B7/00
CPCC22B7/006C22B60/04C22B3/3846C01G56/001C22B3/44G21C19/46Y02E30/30Y02W30/50Y02P10/20C01G56/004
Inventor 左臣郑卫芳晏太红
Owner CHINA INSTITUTE OF ATOMIC ENERGY
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