Simulation of radiation conditions in contaminated rooms
Method for beta and gamma radiation exposure rate calculations inside the radioactively contaminated buildings is presented. Method is based on the realistic model accounting for removable and irremovable components of the surface contamination. Exposure rate calculations for areas with considerable...
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| Zitieren: | Simulation of radiation conditions in contaminated rooms / V.G. Batiy, D.V. Fedorchenko // Вопросы атомной науки и техники. — 2007. — № 5. — С. 115-117. — Бібліогр.: 2 назв. — англ. |
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irk-123456789-1103992017-01-05T03:02:26Z Simulation of radiation conditions in contaminated rooms Batiy, V.G. Fedorchenko, D.V. Ядернo-физические методы и обработка данных Method for beta and gamma radiation exposure rate calculations inside the radioactively contaminated buildings is presented. Method is based on the realistic model accounting for removable and irremovable components of the surface contamination. Exposure rate calculations for areas with considerable level of surface contamination are presented and discussed. Представлено метод розрахунку потужності дози бета- та гамма-випромінювань всередині забруднених приміщень. Створений метод оснований на реалістичній моделі, який враховує поверхневе забруднення, що знімається та таке, що не знімається. Наведено результати розрахунків для сильно забруднених приміщень об'єкту "Укриття". Представлен метод расчета мощности дозы бета- и гамма-излучений внутри загрязненных помещений. Разработанный метод основан на реалистичной модели с учетом снимаемой и неснимаемой составляющих поверхностного загрязнения. Приведены результаты расчетов для сильно загрязненных помещений объекта "Укрытие". 2007 Article Simulation of radiation conditions in contaminated rooms / V.G. Batiy, D.V. Fedorchenko // Вопросы атомной науки и техники. — 2007. — № 5. — С. 115-117. — Бібліогр.: 2 назв. — англ. 1562-6016 PACS: 28.41Te http://dspace.nbuv.gov.ua/handle/123456789/110399 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Ядернo-физические методы и обработка данных Ядернo-физические методы и обработка данных |
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Ядернo-физические методы и обработка данных Ядернo-физические методы и обработка данных Batiy, V.G. Fedorchenko, D.V. Simulation of radiation conditions in contaminated rooms Вопросы атомной науки и техники |
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Method for beta and gamma radiation exposure rate calculations inside the radioactively contaminated buildings is presented. Method is based on the realistic model accounting for removable and irremovable components of the surface contamination. Exposure rate calculations for areas with considerable level of surface contamination are presented and discussed. |
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Article |
| author |
Batiy, V.G. Fedorchenko, D.V. |
| author_facet |
Batiy, V.G. Fedorchenko, D.V. |
| author_sort |
Batiy, V.G. |
| title |
Simulation of radiation conditions in contaminated rooms |
| title_short |
Simulation of radiation conditions in contaminated rooms |
| title_full |
Simulation of radiation conditions in contaminated rooms |
| title_fullStr |
Simulation of radiation conditions in contaminated rooms |
| title_full_unstemmed |
Simulation of radiation conditions in contaminated rooms |
| title_sort |
simulation of radiation conditions in contaminated rooms |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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2007 |
| topic_facet |
Ядернo-физические методы и обработка данных |
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http://dspace.nbuv.gov.ua/handle/123456789/110399 |
| citation_txt |
Simulation of radiation conditions in contaminated rooms / V.G. Batiy, D.V. Fedorchenko // Вопросы атомной науки и техники. — 2007. — № 5. — С. 115-117. — Бібліогр.: 2 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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AT batiyvg simulationofradiationconditionsincontaminatedrooms AT fedorchenkodv simulationofradiationconditionsincontaminatedrooms |
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2025-07-08T00:34:02Z |
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2025-07-08T00:34:02Z |
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1837036830322589696 |
| fulltext |
SIMULATION OF RADIATION CONDITIONS IN
CONTAMINATED ROOMS
V.G. Batiy1, D.V. Fedorchenko2∗
1Institute for Safety Problems of Nuclear Power Plants, 07270, Chernobyl, Ukraine
2National Science Center ”Kharkov Institute of Physics and Technology”, 61108, Kharkov, Ukraine
(Received March 19, 2007)
Method for beta and gamma radiation exposure rate calculations inside the radioactively contaminated buildings
is presented. Method is based on the realistic model accounting for removable and irremovable components of the
surface contamination. Exposure rate calculations for areas with considerable level of surface contamination are
presented and discussed.
PACS: 28.41Te
1. INTRODUCTION
Work activities inside radioactively polluted facil-
ities require radiation environment assessment. Two
factors contribute to the resulting radiation fields: lo-
cal radiation sources and surface contamination. The
first are usually removed during the preliminary de-
activation activities together with the part of surface
contamination. Thus in the absence of local radiation
sources surface contamination solely determines inte-
rior radiation environment. The remaining surface
contamination is constituted by removable and irre-
movable components. Existing experimental meth-
ods allow efficient removable component evaluation.
At the same time assessment of the irremovable con-
tamination is a rather complicated procedure. So
usually only removable contamination is measured.
At the same time contribution of the irremovable con-
tamination to the total exposure rate could be rather
significant. In this paper we present the method of
total (and irremovable) surface contamination recon-
struction based on data on removable contamination.
Assessment of radiation environment for the ”Shelter
object” (SO) of Chernobyl NPP using this method is
also presented and discussed.
2. REMOVABLE AND IRREMOVABLE
CONTAMINATION ANALYSIS
Irremovable contamination is formed mainly by
radioactive sediments diffusion into construction ma-
terial surface layer. Another possibility is surface de-
position of the high-temperature radioactive aerosol.
The last likely took place during the accident on
the Chernobyl NPP in 1986. Surface contamination
amount depends on a variety of factors. The most
significant are radioactive aerosol initial amount and
composition, surface adhesion, interior aerodynamic
conditions. Usually building inner space is divided
into isolated ares such as rooms, airshafts, lift shafts,
etc. Surface contamination formation conditions are
specific to each area. We can assume removable
and irremovable contamination ratio be characteris-
tic constant for every isolated area.
The starting point of our analysis was statisti-
cal analysis of removable contamination and expo-
sure rate ratio. As an example we considered data
for SO room 7001. For this area exposure rate and
removable surface contamination are known for 10
surface locations. Statistical analysis of removable
contamination and exposure rate ratio gives average
value βr = 655± 83 (particles/(cm2 ·min))/(mR/h)
with 0.95 reliability level. This value was used for
further analysis.
SO room 4000 is situated near room 7001
and seems to have similar contamination forma-
tion conditions. Detailed data on surface con-
tamination and exposure rate are available and
were used for verification purposes. Calculated
removable surface contamination levels fall within
the 4.5 · 103 − 59 · 103 (particles/(cm2 ·min) inter-
val. This is in good agreement with experimental
values of 5 · 103 − 80 · 103 (particles/(cm2 ·min).
Observable exposure rate for contaminated area
is governed by total surface contamination. So we
have developed calculation scheme for exposure rate
calculations. It implemented point-source kernel
method with buildup factor. Analytical expression
for buildup factor was taken from handbook [1]. The
final value of βt = 105 particles/(cm2 ·min)/(mR/h)
for the total surface contamination and exposure
rate ratio was obtained. Analytical expressions used
for calculations are linear on surface contamination
value. Thus total surface contamination could be eas-
ily recalculated using βt factor.
Factors βt and βr for the selected area al-
low total and removable surface contamination ra-
∗Corresponding author. E-mail address: d.fedorchenko@gmail.com
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY, 2007, N5.
Series: Nuclear Physics Investigations (48), p.115-117.
115
tio calculation. For the SO room 7001 this ra-
tio is α = βt/βr ≈ 150. Using α for the observed
values of removable contamination total contami-
nation level of 4 · 107 particles/(cm2 ·min) for the
most polluted region near the vent was obtained.
Corresponding calculations for the room 4004 hav-
ing similar conditions gave maximum level of above
5 · 106 particles/(cm2 ·min) for total surface con-
tamination.
3. RESULTS OF CALCULATIONS AND
DISCUSSION
Some work activities inside SO required personnel
presence inside the vent header. Radiation environ-
ment inside the vent header was unknown. Assess-
ment of the exposure rate required assumption on the
surface contamination inside the vent header. For the
calculations we have assumed surface contamination
at upper and lower ends of the vent header to be the
same as that at adjacent areas of rooms 7001 and
4004 correspondingly. Contamination Height distri-
bution of the surface contamination was assumed to
satisfy parabolic law.
Surface contamination for adjacent areas was
fount using the method discussed in the previous sec-
tion. Fitting this values we obtained parameters of
the parabolic height distribution. So total contami-
nation value for every surface point could be easily
calculated. This allowed to use point-source kernel
method to calculate exposure rate spatial distribution
inside the vent header. Doze distribution along the
horizontal section of vent header is shown on Fig.1.
Fig.1. Doze rate inside the airshaft (mZv/h)
High levels of surface contamination in SO room
7001 have set up problem of shielding optimization
according to ALARA principle. During the optimiza-
tion procedure Room 7001 was divided into square
areas (2× 2)m2 in accordance with the experimental
scheme of exposure rate measurements. Total surface
contamination for each square was calculated using
using method developed in section 2.
On the next step two shielding configurations of
the most contaminated areas near the vent header
were considered. Shield was constituted by 10mm
thick lead plates with total square of 48 m2 and
64 m2. Using data on surface contamination we calcu-
lated exposure rate spatial distribution at work area.
Obtained values showed shielding to be ineffective.
Attenuation factor for work area was only 3.5−3.7 for
both configurations while personnel irradiation dur-
ing shielding mounting had increased significantly. So
using ALARA principle shielding was rejected.
Estimations of the total surface contamination
were also used for personnel β-irradiation hazard
analysis inside SO room 4004. For conservative rea-
sons the highest total surface contamination value
7.5 · 106 particles/(cm2 ·min) was taken for calcula-
tions. 90Sr and 90Y activities were taken according
to the averaged fuel radionuclide composition.
Calculations of the β-radiation exposure rate (see
Fig.2) showed surface eye lens exposure doze have
reached limiting value (150 mZv) in less then an hour.
Skin exposure doze have reaches its limit (500 mZv)
in less then 3 hours.
As it follows from our calculations (see Fig.2)
near the contaminated surface eye lens exposure
doze reaches limiting value (150 mZv) [2] in less
then an hour and open skin exposure doze reaches
its limit (500 mZv) [2] in less then 3 hours. From
Fig.2 it also follows that exposure rate at 3 m
away from the surface decreases only by a fac-
tor of 10. Such radiation environment requires
obligatory usage of personnel protective equipment.
Fig.2. β-radiation exposure rate attenuation in air
Calculations for the same radiation conditions with
plexiglass shielding of 1, 2 and 3 mm thickness
showed crucial improvement of the working condi-
tions. For example, even the 1 mm plexiglass shield-
ing increases permissible work time from 1 to 500
hours. In this case β-radiation no longer is the limit-
ing factor as γ-radiation doze limit is reached in 250
hours.
The presented calculations for real-life radiation
environment (”Shelter” object) have proved method
effectiveness for various problems concerning radia-
tion hazard in polluted facilities. This method could
be successfully used for various practical tasks con-
cerning nuclear energetics.
116
REFERENCES
1. V.P. Mashkovich. Protection for ionizing radia-
tion. Handbook. M.: ”Energoizdat”, 1982, 296 p.
2. Norms of radiation safety of Ukraine. NRBU-97.
GGN 6.6.1.-6.5.001-98. Kyiv. 1997, 121 p.
МОДЕЛИРОВАНИЕ РАДИАЦИОННОЙ ОБСТАНОВКИ В ЗАГРЯЗНЕННЫХ
ПОМЕЩЕНИЯХ
В.Г. Батий, Д.В. Федорченко
Представлен метод расчета мощности дозы бета- и гамма-излучений внутри загрязненных поме-
щений. Разработанный метод основан на реалистичной модели с учетом снимаемой и неснимаемой
составляющих поверхностного загрязнения. Приведены результаты расчетов для сильно загрязнен-
ных помещений объекта "Укрытие".
МОДЕЛЮВАННЯ РАДIАЦIЙНОЇ ОБСТАНОВКИ У ЗАБРУДНЕНИХ
ПРИМIЩЕННЯХ
В.Г. Батiй, Д.В. Федорченко
Представлено метод розрахунку потужностi дози бета- та гамма-випромiнювань всерединi забруд-
нених примiщень. Створений метод оснований на реалiстичнiй моделi, який враховує поверхневе за-
бруднення, що знiмається та таке, що не знiмається. Наведено результати розрахункiв для сильно
забруднених примiщень об’єкту "Укриття".
117
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