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UNIVERSITY OF NIFACULTY OF OCCUPATIONAL SAFETY IN NI

PROCEEDINGSThe 16th Conference of the series Man and Working Environment

INTERNATIONAL CONFERENCESAFETY OF TECHNICAL SYSTEMS IN LIVING AND WORKING ENVIRONMENT

Endorsed by:Government of the Republic of Serbia

MINISTRY OF EDUCATION AND SCIENCE

Ni, 27-28 October 2011

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UNIVERSITY OF NISFACULTY OF OCCUPATIONAL SAFETY IN NI

PROCEEDINGSThe 16th Conference of the series Man and Working Environment

INTERNATIONAL CONFERENCESAFETY OF TECHNICAL SYSTEMS IN LIVING AND WORKING ENVIRONMENT

PUBLISHED BY:FACULTY OF OCCUPATIONAL SAFETY IN NIS

arnojevi a 10a, 18000 Ni

FOR THE PUBLISHER:

Prof. dr Ljiljana ivkovi , dean

EDITORS OF PROCEEDINGS:Prof. Dejan Petkovi , PhD

Prof. Ivan Krsti , PhD

GRAPHIC DESIGN AND PREPRESS:Rodoljub Avramovi

PRINTED BY:M COPS CENTER, Ni

CIRCULATION:300 copies

CIP -

,

331.45/.46(082)

502/504(082)614.8.084(082)

INTERNATIONAL Conference of the Series Man

and Working Environment Safety of TechnicalSystems in Living and Working Environment (16; 2011 ; Ni)Proceedings / The 16th InternationalConference of the Series Man and WorkingEnvironment Safety of Technical Systems in

Living and Working Environment - [STS-11],Ni, 27-28 October 2011. ; [organizer Facultyof Occupational Safety in Ni ; editors DejanPetkovi , Ivan Krsti ]. - Ni : Faculty ofOccupational Safety, 2011 (Ni : M KopsCentar). - 493 str. : ilustr. ; 30 cm

Slike autora i beleke o njima. - Tira 300.- Bibliografija uz svaki rad.

ISBN 978-86-6093-035-61. Fakultet zatite na radu (Ni)a) - b)

- - c)-

COBISS.SR-ID 187155980

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NICOLAY BARBIN1

DMITRY TERENTEV2

SERGEI ALEXEEV3

SERGEI ORLOV4

Ural Institute of State FireService of Emercom of Russia

1NMBarbin@yandex.ru

2svireppey@mail.ru33608113@mail.ru43608040@mail.ru

THERMODYNAMIC MODELLING FOR

BURNING OF RADIOACTIVE GRAPHITE

Abstract: This study deals with carbon oxidation and physical-

chemical transformations of radioactive elements during the

combustion graphite waste in the atomic power industry. The methodof thermodynamic simulation was used.

Key words: radioactive graphite, thermodynamic modelling, burning.

INTRODUCTIONGraphite reactors are widely used in nuclear power. It

usually burns in the heterogeneous mode. The crystal

structure of a graphite is deformed by action of theWigner effect at 473520 K. The Wigner energy haspossibilities for accumulation into a graphite to a

certain value, and then it can spontaneously go out andcreate a condition for occurrence of a fire [1]. Aradioactive black lead contains various radio nuclides,such as hyzone and 14 , and also corrosion/activationproducts (57 , 60 ; 54Mn; 59Ni; 63Ni; 22Na etc.),fission products (134Cs, |37 , 90Sr, l52Eu, 144 etc.) and a

small amount of uranium and transformation elements(

238Pu,

239u,

241Am,

243Am etc. [2]. Radio elements are

remained with a nonflammable part, or are evaporated

depending on degree of their fugitiveness. Gaseousradio elements are condensed on larger particles. Takenout submicrometer particles are easily inhaled in lungs.They can also be postponed at a surface of reservoirs

and at food cultures.

RESULTS AND DISCUSSION

In this paper evaporation and condensation of radioelements are investigated at burning of radioactive

black lead by the method of thermodynamic modelling.TERRA soft is applied for calculations of equilibriumstates for complex heterophase systems [3]. There are

thermodynamic functions of 33 condensed and 35elementary gases and compounds are used atcalculation.

UO2, UOCl, UOCl2, CaCl2, BeO are the majorcomponents into the condensed phase. Their

concentrations are more than 10~2 molar shares. UO2 isbecome the dominated component at 1300 to 1500and its concentration is about 0.98 molar shares.

The main components of a gas phase are N2 ( ~0,98

bar), O2 and CO ( ~10-1

bar) at temperature above900 .

Carbon is passed into a gas phase as CO and 2 in the

relation 1:1 at temperature more than 900 K.Distribution of cesium on phases is resulted in fig 1.

About 100 % of cesium is existed as the condensed

CsCl at temperature 300-700 . Rise of temperature to900-1400 is resulted to 100 % transferring of chlorideof cesium in a gas phase.

Phase allocations of calcium and strontium are brought

in figs 2 and 3. Calcium and strontium exist ascondensed SaSl2 and Sr l2 at temperature 300-1000 K.

Increase of temperature to 1300 K is yielded totransferring of these chlorides in a gas phase.

Figure 1.Distribution of cesium on phases

Figure 2.Distribution ofcalciumon phases

At temperature 300-900 K approximately 100-90 % ofberyllium exists in the form of condensed BeO.

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Safety of Technical Systems in Living and Working Environment - STS 2011, October 27-28, 2011, Ni, Serbia

In the range of temperatures from 800 to 1200 K thecontent of condensed BeO is decreased from 90 to 5 %

and a percentage share of gaseous BeCl2 is increasedfrom 10 to 95 % because passing of the next chemicalreaction.

BeO + C + Cl2 BeCl2 + CO

Figure 3.Distribution ofstrontiumon phases

Figure 4.Distribution ofberylliumon phases

The further increasing of temperature to 1600 iscarried on to shift of equilibrium of the reaction to theleft (growth of the condensed share of BeO to 95 %and reduction of the gaseous share of BeCl2 to 5 %).

The nickel distribution on phases is resulted on fig. 5.

At temperature 300-700 approximately 100-97 % ofnickel is been in the condensed state of NiCl. Rise oftemperature to 900 K is leaded to sharp reduction the

condensed phase of NiCl practically to zero and toincrease the gaseous phase of NiCl2 to 100 %. In therange of temperatures 900-1400 K the all nickel is been

in the gaseous state of NiCl. The further rise oftemperature to 1600 K is given to reduction of thegaseous share of NiCl2 to 60 % and to lead to

occurrence of the gaseous form of NiCl to 30 %.

The uranium distribution on phases is shown on fig. 6.

In a temperature band 300-700 K uranium has existed

in the condensed phases of UO2, UOCl, UOCl2.

At 1100 the concentration of the gaseous state ofUCl4 is reached to 12 % and concentration of thecondensed UOCl2 is fallen to zero. The further rise oftemperature to 1300 conducts to disappearance of thegas phase of UCl2 and the condensed UOCl, anduranium is been as the condensed UO2. All uranium is

existed in condensed state of UO2 in a temperatureband from 1300 to 1600 .

Figure 5.Distribution of nickelon phases

Figure 6.Distribution of uraniumon phases

Plutonium distribution on phases is resulted on fig. 7.

At 300 all plutonium is been as the condensed PuCl3.In a temperature band from 800 to 1300 there arebasic chemical transformations, disappears of the

condensed PuCl3, occurs of the gaseous PuCl4 (~10 %),the condensed PuOCl (~75 %) and the condensedPuO2. At the further rise of temperature to 1600 isled to the condensed PuO2 as the major form of

plutonium.

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Figure 8.Distribution of americiumon phases

Figure 7.Distribution of plutonium on phases

Europium distribution on phases is resulted on fig. 8. In

a temperature band from 300 to 600 there is increase

of the condensed EuCl2 share and reduction of thecondensed EuCl3 share. In a temperature band from 600

to 900 all europium is been in the form of thecondensed EuCl2. In a temperature band from 900 to1300 there is reduction of the condensed EuCl2content and increase of the gaseous EuCl3 content to80 %. The further temperature increase to 1600conducts to reduction of the quantity of gaseous EuCl3

to 30 %, the condensed EuCl2 to 10 % and increase ofthe content of the condensed Eu2O3 to 30 % and thecondensed forms of EuOCl to 20 %, and EuO to 10 %.

REFERENCES

[1] A.K. Mikeev: Fire-Prevention Atomic Power StationProtection, Energoatomizdat (Rus. Ed.), 1990, Moscow.

[2] N.M. Barbin, A.V. Peshkov, M.P. Dalkov, D.I. Terentev,

S.G. Alexeev: Estimation of Behavior of Radio

Nuclides at Burning of Radioactive Black Lead Proc.

The II Allrussian Science and Technology Conference,

Symposium and XII School of Young Scientists, 2008,

p. 67.

[3] G.K. Moiseyev, G.P. Vyatkin, N.M. Barbin: Application

of thermodynamic modelling for studying of interaction

with participation of ionic melts, SUSU, 2002,

Chelyabinsk.

Figure 8.Distribution of europiumon phases

Americium distribution on phases is shown on fig. 9.

In the range of temperatures from 300 to 800 allamericium is presented in the condensed form ofAmO2. Rise of temperature to 1600 is resulted tooccurrence of condensed Am2O3 (~10 %) and otheramericium is existed as the condensed AmO2 (~90 %).

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