JPS59166885A - Density measuring method of radioactive collected substance - Google Patents

Abstract

PURPOSE:To measure automatically the concentration degree of a radioactive collected substance in a tape from the outside of the trap by installing a gamma ray detector opposite by to a gamma ray source through the trap in the vicinity of the outside wall of the trap. CONSTITUTION:The intensities I2, I1 of a gamma ray before and after a substance A is collected are measured by using a gamma ray detector 3 which irradiates a gamma ray to a radioactive substance A collector in a trap 1 by a gamma ray source, to detect the weight of said radioactive substance, to measure the a gamma ray transmissibility, and the weight of a radioactive collected substance B is detected by measuring a gamma ray peculiar to said radioactive collected substance emitted from the radioactive collected substance B in said trap, and subsequently, the ratio of the weight detected value occupied in said weight detected value derives the concentration degree of the radioactive collected substance B in the radioactive collected substance A by using known various constants and by a theroy expression. In this way, the concentration degree of the radioactive collected substance B in the radioactive collected substance A in the trap 1 can be measured automatically from the outside of the trap.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the concentration of radioactive trapped substances, in which γ, ? Measure the γ-ray transmittance when irradiated with # to detect the overlapping of the same radioactive collection material, and measure the γ-rays unique to the radioactive collection material emitted from the radioactive collection material in the trap. and detecting the weight of the radioactive collection material, and then measuring the concentration of the radioactive collection material in the radioactive collection material from the ratio of the detected weight value to the detected weight value. The purpose of this invention is to provide a method for measuring the concentration of a radioactive trap, which can automatically measure the concentration of a radioactive trap in a radioactive trap in a trap from outside the trap.

Next, the method for measuring the concentration of radioactive substances according to the present invention will be explained using an example shown in FIG.
) is the γ-ray source installed near the outer wall of the trap (1), (3) is the γ-ray detector installed to face the same γ-ray source (2) via the trap flY, and (1α) is the trap Inlet of H, (1h) is the outlet of trap (11, filled with radioactive collecting substance (hereinafter referred to as scavenger 5) (B) (collecting agent that collects the radioactive substance to be captured (A)) In the trap (1), a radioactive material to be collected (a collector agent (Bl) is distributed like a parallel oblique section), and a γ-ray source (
2) to the center of the trap (11), and the gamma rays transmitted through the trap (11) to the gamma ray detector (3)
It is now detected by .

Next, the operation of the measuring device will be explained. (I) Parallel shaded area (the zone of the substance to be captured (N+ scavenger (day) grows,
When you reach the exit (1h) of trap (11), trap (1
) will become unusable, so you must replace the scavenger (levelling agent) before that happens.For this, we will do the following 5.

That is, the γ-ray source (2) and the γ-ray detector (3) are trapped (
1) in the vertical direction along 5. At this time, the absorption rate of γ-rays is different depending on whether or not there is a substance to be collected (Shu) in the trapping agent (B) in the trap (1), so due to the vertical movement, You can see how much the parallel shaded area (substance to be collected (A), collection agent (B)) in the trap (11) has grown, and if it has grown, the trap (seagull) (+1)Next, we will explain the weight measurement of the substance to be collected (A).Generally, the strength of the γ-ray source (2) is 0, and the strength of the γ-ray after transmission is Rate E
If a, I=E ・Eng ......(11α
There is a relationship between
If the thickness of the substance is X, then B is Bild 9
2, As a coefficient, E, = B, x pc-μx) (2)
As shown in Fig. 1, the location where the radioactive liquid collecting substance (A) is collected is Ettt = t/ko = B1"PC-μs"o-μ
2x2)...(3) However, μm, I2: Collection agent (B)
and the linear absorption coefficient of substance (A) 3:1. r a: Length of the zone containing only the scavenger (B) I2: Length of the zone containing the scavenger B + substance A In place, E, a
2= I□/Io= B, eXp<-μm”O)
・・・・・・(4) From formula (3) and formula (4), K = EcL2/E,, = 1.2/I□= gX
P(I2”2) −(53 therefore I2・:t2= 71L(I2/I,)
...(6) Also, if the density of the substance is ρ, the linear absorption coefficient μ and mass absorption coefficient μ are μ2μ.・ρ...Equation (7) (
7) by substituting K into equation (6), ρ2=' n (Work2/I 1 )/μm2・I2
...(8) In formula (8), I2 cannot be measured directly, so if t2=xo and the density of substance (A) is ρ2/, then ρ2'= 1rL(I 2 / I 1 )/ p, Tn
2・xo...(9) Trap (length Y of 11
When L, the volume V of trap (1) is: ■=π:co L/4 −u(1
Therefore, the weight W2 of the substance (A) collected by 1 is W2=ρ
2'・v-π・xo-L=ln(work 2/work 1)/4μm
z'=(ID In formula (11), π, xo, L,
Since prn2 is a known value, the amount of collected substance (A) can be determined by measuring the γ-ray intensities I2 and 11' before and after the substance (A) is collected. (Ill) Next, measurement of concentration will be explained.

When there is a collecting agent (radioactive collecting substance) in the collected substance (A), when gamma rays emitted from the collecting agent (Ee) are measured, it is found that the collecting agent (B) is The amount present can be determined. Collection agent (
B) When there are N (radioactive nuclides), their decay rate Q is given by the decay constant λ, Q=Nλ...(12+On the other hand, the counting rate of γ-rays of that nuclide is n=Q-E , , η-EoL-Qa) However, Ee: γ-ray emission vehicle of the nuclide η 2 Counting efficiency of the γ-ray detector Ea: Transmittance of γ-rays in a substance and weight Wn of N nuclides is W ', = N-M/Ao...0
4) However, 1M: the amount of M per 1 molJ of the nuclide Ao: Avogadro's number On the other hand, the material obtained by formula a (the weight of the nuclide of interest in 8)'M-WJ is W'2α・W2... (15) However, α: weight ratio formula of the nuclide of interest in the substance (A) (121・α
31 into equation (14), WrL= (n/E, -η
-Ea-λ)M/Ao-・-06) From the formula (151, μQ), the uranium enrichment ε is ε-WrL/%%j = tt-M
/Ao-E, -η-E, :L-λ・α・W2・-aD On the formula side, M%Ao, E, η, Ea, λ, σ,
Since W2 is known, ε=C□・ru...α81
However, C□=M/Ao-E, η-Ea-λ・α-w2
The method for measuring the concentration of a radiation trapping substance of the present invention is to measure the gamma ray transmittance when the radioactive trapping substance collected in the trap is irradiated with gamma rays as described above. The weight of the radioactive collecting material is detected by measuring the gamma rays peculiar to the radioactive collecting material emitted from the radioactive collecting material in the trap, and then the weight of the same detected weight is measured. Since the concentration of the radioactive collection material in the radioactive collection material is measured from the proportion of the detected value, the concentration of the radioactive collection material in the radioactive collection material in the trap can be automatically measured from outside the trap. There is an effect that can be done.

Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

[Brief explanation of drawings]

FIG. 1 is a side view showing an example of a measuring device used to carry out the method for measuring the concentration of a radioactive trapping substance according to the present invention. (A)...Radioactive capture substance, (odor...Radioactive capture substance, (i)...Trap, (2)...γ-ray source, (
3)...Gamma-ray detector sub-agent patent attorney Shige Okamoto (2 persons) Figure 1

Claims (1)

[Claims] When gamma rays are irradiated to the radioactive material collected in the trap, the gamma ray transmittance is measured, the weight of the radioactive material is detected, and the weight of the radioactive material is detected and released from the radioactive material in the trap. The weight of the radioactive collecting material is detected by measuring γ1Illjl which is unique to the radioactive collecting material, and then the radioactive collecting material in the radioactive collecting material is determined from the ratio of the detected weight value to the detected weight value. A method for measuring the concentration of a radioactive collection substance, the method comprising measuring the concentration of a radioactive collection substance.