The 12th International Conference on Environmental ... - Events

Session 22 Abstracts
E) CFD STUDIES OF VORTEX AMPLIFIER DESIGN IN THE
CONTEXT OF SELLAFIELD NUCLEAR OPERATIONS - 16061
Martin J Birch, John Tyndall Institute for Nuclear Research (UK); Darren Parker, Land Securities Trillium (UK);
Jonathan Francis, University of Central Lancashire (UK); Raymond Doig, Sellafield Limited
<strong>The</strong> use of computational fluid dynamics (CFD) has had a substantial impact on the cost and nature of design studies involving
both external flows (e.g. aerofoils) and internal flowsthrough components (e.g. valve design); CFD packages are now used
extensively throughout the engineering community. <strong>The</strong> commercial software 'CFX' was used to conduct design studies of vortex
amplifier geometry. <strong>The</strong> use of the code has been validated by comparing the results of the simulations with experimental data. <strong>The</strong>
code is now being used to study changes to the geometry of the vortex amplifier that could not be reproduced experimentally at an
equivalent cost.
This paper reports on progress and current developments. <strong>The</strong> anomalous reverse flow in the supply ports of the mini-VXA
has been captured and the mixing in both the chamber and the precessing vortex core also appears to have been successfully reproduced.
F) DECOMMISSIONING OF A URANIUM CONVERSION PLANT AND
A LOW LEVEL RADIOACTIVE WASTE FOR A LONG TERM DISPOSAL - 16071
Yun D. Choi, D.S. Hwang, U.S. Chung, Korea Atomic EnergyResearch Institute (Korea)
In the middle of 2004, a decommissioning program for a conversion plant, which was constructed in 1982, and treated about
300 tons of natural uranium until it was shut down in 1992, obtained its approval of the regulatory body. Actual dismantling and
decontaminating activities have been performed since the July 2004 and will be terminated in December 2009.
<strong>The</strong> decommissioning works were mainly divided into two parts, for the inside of the building containing the process equipments
and for the lagoon sludges generated during the plant operation. <strong>The</strong> decommissioning for the inside of the building was carried
out by dismantling the process equipments, which were firstly segmented and decotaminated by a polishing and a washing with
steam and chemicals or a melting, and then a decontamination for the surfaces inside the building by scrabbling or grinding the
concrete walls. <strong>The</strong> decontamination goals were below 0.2Bq/g for the matallic segments and below 0.4Bq/g for the concrete walls.
A decontamination methods were selected according to the degree of contamination and a minimization of the low level radioactive
wastes was conducted throught the decommissioning works.
Lagoon sludge wastes had two types, one was an various inorganic nitrate salt mixture containing a very low concentration of
uranium, about 200~300ppm, in Lgoon-II and the other was an inorganic nitrate salt mixture containing a few percent of uranium
in Lagoon-I. To treat these sludge wastes a thermal decomposition facility was constructed and operated to produce stable sludge
wastes contained triuranium octoxides which are stable in the air. <strong>The</strong> final sludge wastes after a thermal treating for the sludge
waste of lagoon-I could be reused.
<strong>The</strong> final residual radioactivities for the inside of the building will be measured to cofirm a complete decontamination of the
uranium to back ground level and then the building will be considered for an other use.
G) REHABILITATION PROJECT FOR PODOLSK NONFERROUS METALS PLANT - 16136
Alexander V. Chesnokov, Victor G. Volkov, Anatoly Volkovich,Alexey Lemus,
Vitaly Pavlenko, Sergey Semenov, Russian Research Center “Kurchatov Institute”(Russia);
Maxim Gizay, Sergey Krahotkin, FSUE Federal Property Management Center (Russia)
Radioactive contamination of the site and facilities of Podolsk Nonferrous Metals Plant (PNMP) caused by unauthorized delivery
of a radioactive source among scrap metal to the plants melt shop refinery has occurred in 1989. As a result, the refinery premises
and adjacent territory, department of construction activity warehouse, internal railway branch, scrap metal site and two open
slag collectors were contaminated with 137Cs radionuclides.
Between 1989 and 2001, after site decontamination works, the waste belonging to MLW category was removed from the plants
operating zones and sent to MosNPO Radon for long-term storage. Waste belonging to LLW category was accumulated on several
dedicated sites and in the melt shop department. Secondary contamination of the internal railway branch and department of construction
activity warehouse took place as a result of decontamination activities.
It should be noted that no comprehensive engineering and radiation survey of contaminated facilities and site of PNMP has
ever been performed. Though the contaminated area is situated in the immediate vicinity of the Petritsa River, and there is a risk of
its contamination with radionuclides, no comprehensive study of radionuclide contents in subsurface and ground waters, as well as
no radionuclide migration study, has been performed.
In 1992-1993, Federal State Unitary Enterprise State Specialized Design Institute(FSUE SSDI) has developed a work project
entitled Elimination of radioactive contamination consequences and interim radwaste repository construction at PNMP. <strong>The</strong> project
was updated in 1997, 2001 and 2005. It provided for constructing a regional on-site interim radwaste repository at the PNMP
site.
H) REMOTE RADIATION SENSOR BASED ON EPOXY RESIN AND OPTICAL
FIBER FOR MONITORING OF HIGH-LEVEL DECOMMISSIONING FACILITIES - 16160
Bum-Kyoung Seo, Chan-Hee Park, Dong-Gyu Lee, Kune-Woo Lee, Korea Atomic Energy Research Institute (Korea)
It’s important to survey the radiation level in the nuclear facilities to be decommissioned. In some facilities such as hot-cell the
radiation level is very high. So it is difficult to approach for monitoring the radioactive contamination. In this case the detector system
is preferable to separate the sensor and electronics, which have to locate in the facility outside to avoid the electric noise and
worker’s exposure.
In this study the remote radiation sensor for radiation and contamination monitoring of the decommissioning facility was developed.
<strong>The</strong> radiation sensor was prepared using a transparent epoxy resin and a scintillator. <strong>The</strong> used scintillators were an organic
for gamma-rays and inorganic one for alpha particles.
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