Файл: Исследование суточных вариаций поровой активности радона в поверхностных грунтах удк 550. 42 546. 296 551. 51.docx

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PLANNED RESULTS OF THE DEVELOPMENT OF THE PLO/OPOP

SYMBOLS AND ABBREVIATIONS

Introduction

1 Chapter

Areas applications quantities density flow radon

Climatology. Radon - as a tracer of air exchangeprocesses

Static and dynamic methods measurements

Chapter

Dynamics of radon activity and its decay products inside the storage chamber

Conclusion on the chapter The field of β-radiation at depths of 0.5 and 1 m quite well reflects the dynamics of the radon subsoil field, the daily variation is well traced. However, the daily course of the β-field in some periods has a shift compared to the daily course of the radon field, i.e. the time of the onset of the maximum in the dynamics of the β-field is ahead/late by several hours.The dynamics of RA of radon in soil air at the same depth, but at a distance of 1.5–2 m, can differ significantly. The maxima in the daily course of RA of radon at different depths occur at different times, at a depth of 0.5 m - approximately at 16-18 hours, and at a depth of 1 m - at 24 hours. The delay in some periods reaches 8 hours.Correlation analysis between the radon field and meteorological values revealed only a significant relationship with the amount of rainfall.A 2-month experiment on the calibration of β- and α-radiation detectors installed in wells did not make it possible to unambiguously determine the correction factors for converting to units of volumetric activity. As a result, it was decided to conduct a second experiment with some adjustment of the experimental design, as well as refinement of the VA detector installation scheme. The requirements for the conditions for calibrating the readings of the VA detector in units of RA of radon are as follows: Wells with VA detectors installed inside should not be opened during calibration, i.e. tubes for pumping air from the well, which are cyclically connected to the radon radiometer, should be installed at least a day before the start of the experiment. The VA detectors should not be removed from the well or moved in the well during calibration, as this leads to a distortion of the time series of data. To calculate the coefficient of decrease in the range of diurnal variations after the start of pumping air from the well, it is necessary to record data from the VA detector at least a week before the start of the experiment, and after its completion. The development of the project infrastructure made it possible to analyze the results of the calibration of soil detectors by 0.5 and 1 мusing a radon radiometer, which showed the following:at depth, 0,5 мthe temporal changes in the α- and β-fields are practically synchronous, but have different amplitudes ;in the daily course of radon VA at different depths, the maxima at depth 0,5 мare recorded at 16–18 h, and at depth 1 мat 24 h; the delay in time of the moments of the onset of maxima in radon VA is

Chapter 4 Financial management, resource efficiency and resource saving

Consumer portrait

SWOT analysis

Project Initiation

Project Participants

Project Schedule

Scientific and technical research budget

Basic salary

Additional salary

Overhead costs

Conclusion

Social responsibility

Industrial safety

Artificial lighting

Electrical safety

Static electricity

Safety in emergencies

Conclusions to the section social security

List of sources used

application 1

is optional knowledge of the value of the advection velocity, since it is based on the use of already measured values of radon volumetric activity in soil air on depth up to 1 meters. Method developed in 3rd options.

First option method By estimates density flow radon

In this method, you can limit yourself to one measurement of the volume activity soil radon and use information O physical geological parameters soils For estimates values ???? . Denote

measured on depth h concentration radon ???? ( ) = ???? .

Substitute in

the equation (2)
(2)

Express coefficient at exhibitor in next form
(3)

In accordance with Fick's law and taking into account radiological transferintensity flow radon determined expression (4).
(4)

with taking into account (2) at ???? = 0 expression (4) will accept

view

(5)

Let's write down expression (6) rewriting the equation (5), With taking into account (3) we getformula For estimates density flow radon With surfaces land By measured on certain depth volumetric activity radon in soil air.
(6)

At absence credible information O physical and geological soil parameters instead of values ???? Can use in calculations, along with With ???? , meaning voluminous activity radon, measured on another

depth.

Second option method By estimates density flow radon

When measurements volumetric activity radon produced on depths that differ by 2 times, the second option is more useful method By estimates density flow radon. Substitute in the equation (2) values of radon volumetric activity
???? 1 and ???? 2 measured at depths 1 and ℎ2

_ we get expressions (7) and (2;7)

???? 1 = ???? ( 1 ???????????? ???? 1 ) , (7)

???? 2 = ???? ( 1 ???????????? ???? 2 ) , (8)

Where

Express ???? and ???? through ???? 1 and ???? 2 . in case, When ℎ2 _ = 2ℎ 1 , systemequations (7; 8) It has simple analytical solution. Denote

???????????? ???? 1 = , Then ???????????? ???? 2 = ???????????? −2???? 1 = ???? 2 and equations (7; 8) accept view
???? 1 = ???? ( 1 ???? ) , (9)

???? 2 = ???? ( 1 ???? 2 ) , (10)

Dividing ???? 2 and ???? 1 and taking a logarithm both parts equations, we getformula For ????
(11)


Expression For ???? through measured voluminous activity radon

???? 1 and ???? 2 looks next way

(12)

Transforming equation (5), taking into account (11) and (12),

we obtain a formula for estimating the RFD from the earth's surface using radon pore activities measured at depths that differ by a factor of 2
(13)

Third option method By estimates density flow radon

When measurements volumetric activity radon produced on depths that differ by a factor of , the third option is more useful method By estimates density flow radon.

At this ℎ2 _ =???? ℎ1 , _ ratio ???? 1 and ???? 2 is equal to ???? ,

Having made several transformations with equations (9) and (10), we obtain the expression (14)
???????????? _ ???? + ( 1 ???? ) = 0. (14)
The resulting nonlinear equation (14) in the general case cannot be solved analytically, however, numerical methods allow solving this equation to determine the unknown quantity .

The advection velocity is expressed in terms of the desired value

???? in the following way

(15)

Meaning equilibrium voluminous activity radon in soilair

equals

(16)

Taking into account relations (15) and (16), the expression for the radon flux density takes the form
(17)
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Static and dynamic methods measurements


pushing off from designs funded cameras, which used to measure the flux density of radon from the ground surface, measurement methods can be subdivided on two main:

static (Cumulative camera All time be in closed condition. measurements produced directly on accumulated quantityradon in the accumulation chamber, with subsequent measurement, the accumulation camera ventilated.) The method is used more frequently. Dynamic (take place continuous circulation air in storage chamber).

    1. Detectors for measuringpore activity of radon in the surface soil.


Highly sensitive scintillation intelligent detection unit designed to measure the flux density of alpha particles from contaminated surfaces in the range from 0.1 ppm (min·cm2 ).


Figure 3. Scheme installations for measurements density flow radon from the surface soil
where 1 is a storage chamber designed to measure the RFD from the soil surface. The camera is installed in the ground so that the distance from the ground surface to the detector is 10 cm; 2 - detection unit BDPA-01 and BDPB-01.

Applications: Radioecology, sanitary and epidemiological supervision , nuclear industry, fire services, emergency rescue services, civil defense, scientific research.
Table 2 shows the main characteristics of the detection units BDPA-01, BDPB-01 for measuring the density of ionizing radiation fluxes.

Table 2. Main characteristics of detection units


Alpha radiation detection units


Detector

Alpha particle flux density measureme

nt range

239 Pu

surface activity measurement range

Pu alpha particle fluence measureme nt range

Energy range



239 Pu Alpha Sensitivity

imp∙s -1 / part∙min -1

.cm -2



Overall dimensions, weight

Limit of basic relative measurement

error

Degree of

protection


Scintil . ZnS ( Ag ) 30cm 2

0.1-10 5

ppm -1

.cm -2

3.4∙10 -3 -

3.4∙10 3

Bq∙cm -2

1-3∙10 6

part∙cm -2



4-7 MeV



0.15

Ø80x196

mm

0.5 kg

±20%

IP64

Beta radiation detection units




Beta

Surface

Measurem











Detector

particle flux density measureme nt range

activity measurement range 90 Sr + 90 Y

ent range

of fluence of 239 Pu beta

particles


Energy range

Sensitivity to beta radiation of the 90Sr+90Y source imp∙s -1 / part∙min -1

.cm -2

Overall dimensions, weight

Limit of basic relative measurement

Degree of




error







protection



Scintil . Plastic

1-5∙10 5

part∙min

-1 .cm -2

4.4∙10 -2 -

2.2∙10 4

Bq∙cm -2

1-3∙10 6

part∙cm -2


155keV-

3.5 MeV



0.3

Ø80x196m

m

0.5 kg

±20%

3.5 MeV



The method of monitoring the radon flux density from the soil surface consists of the use of a scintillation (or semiconductor) α - particle detector and an accumulation chamber.

α -particle detector is installed inside the accumulation chamber so that its film is located no closer than 10 cm from the soil surface. Such a limitation makes it possible to exclude the “background”, which

can be determined by detecting α -particles resulting from the decay of soil radionuclides.



Figure 4. Scheme of installation of a device for monitoring the density of radon flux from the soil surface
The accumulation chamber has ventilation holes for partial discharge of soil gas and for maintaining a semi-equilibrium concentration of radon inside the accumulation chamber. The number and size of holes are chosen in accordance with the condition that the pulse count rate inside the accumulation chamber must be at least 10 times greater than the pulse count rate in the open atmosphere at the same distance from the scintillation α-detector film from the soil surface. This allows us to reduce the statistical error of the measurement results.
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