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

Session 22-24 Abstracts
M) OXIPROBE — A NON DESTRUCTIVE TOOL FOR DETERMINING STEAM
GENERATOR OXIDE CHARACTERISTICS - 16250
John P., Krasznai, Kinectrics Inc. (Canada)
CANDU Stations are designed with significant amounts of carbon steel piping in the primary circuit. Although the primary
coolant chemistry is such that carbon steel corrosion is minimized, nevertheless magnetite transport from the carbon steel surfaces
to the steam generators is a significant issue leading to potential reduction in heat transfer efficiency in the steam generator. <strong>The</strong>re
are other contributors to the reduction of heat transfer efficiency such as divider plate leakage whereby some of the coolant short
circuits the steam generator tubes and secondary side steam generator tube fouling.
CANDU station operators have utilized a number of mitigating measures such as primary and secondary side mechanical and
chemical tube cleaning, and divider plate refurbishment to counter these problems but these are all expensive and dose intensive,
It is therefore very important to establish the relative contribution of each source to the overall heat transfer degradation problem
so the most effective results are obtained. Tube removal and laboratory assessment of the oxide loading is possible and has been
utilized but at best it provides an incomplete picture since typically only short lengths of tubes are removed most often from the
hot leg and the tube removal process adversely impacts the primary side oxide integrity. Kinectrics Inc. has developed, qualified
and deployed Oxiprobe, a highly mobile non destructive technology cable to remove and quantify the deposited oxide loading on
the primary surfaces of steam generator tubes. <strong>The</strong> technology is deployed during shutdown and provides valuable, direct information
on:
• Primary oxide distribution within the steam generator
• Oxide loading (thickness of oxide) on the primary surfaces of steam generator tubes
• Oxide composition and radiochemical characterization
N) METHODS OF CONTROL OF INACCURACY IN CALCULATION OF NUCLEAR POWER PLANT
DECOMMISSIONING PARAMETERS - 16383
Frantisek Ondra, DECOM, a.s.,(Slovakia); Vladimír Daniaka, Deconta, a.s.,(Slovakia) Ivan Rehak, Decom, a.s.,
(Slovakia);Vladimir Necas, Slovak University of Technology in Bratislava(Slovakia)
<strong>The</strong> aim of the article is a development of analytical methodology for evaluation of input data inaccuracies impact on calculation
of cost and other output decommissioning parameters. This methodology is based on analytical model calculations using the
OMEGA code and taking into account the probability of input data inaccuracies occurrence also.
SESSION 23 - PANEL: CURRENT IAEA ACTIVITIES IN PREDISPOSAL
MANAGEMENT OF L/ILRADIOACTIVE WASTE
ABSTRACTS NOT REQUIRED
SESSION 24 - NATIONAL AND INTERNATIONAL D&D PROGRAMS
1) DECOMMISSIONING IN THE UNITED STATES - PAST, PRESENT AND FUTURE - 16318
Jas S. Devgun, Sargent & Lundy (USA)
<strong>The</strong> experience related to decommissioning of nuclear facilities in the United States is very substantial and covers power reactors,
research reactors, and many facilities in the Department of Energy complex. <strong>The</strong> focus of this paper however is on the commercial
power plants.
With 104 operating reactors, the U.S. fleet of civilian reactors is still the largest in the world. Nuclear power industry in the
United States has undergone a dramatic upturn after decades of stalemate. One effect of this nuclear renaissance has been that the
plans have changed for several reactors that were initially destined for decommissioning. Instead, the focus now is on relicensing
of the reactors and on power uprates. In fact, after the peak period between 1987 and 1998, no additional power reactors have been
shutdown. On the contrary, power uprates in the past twenty years have added a cumulative capacity equivalent to five new reactors.
Almost all the operating reactors plan to have license extensions, thus postponing the eventual decommissioning.
Nevertheless, in addition to the 9 reactors where licenses have been terminated following decommissioning, 12 power and
early demonstration reactors and 14 test & research reactors are permanently shutdown and are in decommissioning phase. Substantial
experience and lessons learned are available from the U.S. projects that are of value to the international decommissioning
projects, especially where such projects are in early stages. <strong>The</strong>se lessons cover a wide array of areas from decommissioning plans,
technology applications, large component removal, regulatory and public interface, decommissioning funding and costs, clean up
criteria, surveys of the decommissioned site, and license termination. Additionally, because of the unavailability of a national spent
fuel disposition facility, most decommissioning sites are constructing above ground interim storage facilities for the spent nuclear
fuel.
2) DECOMMISSIONING STRATEGIES WORLDWIDE: A RE-VISITED OVERVIEW
OF RELEVANT FACTORS - 16016
Michele Laraia, <strong>International</strong> Atomic Energy Agency (IAEA) (Austria)
This paper highlights current trends and developments in selecting decommissioning strategies worldwide. Radiological conditions,
spent fuel and radioactive waste management, funding, economics and the development of suitable technology are some
common factors for taking decisions on the timing and circumstances of decommissioning. Although safe enclosure is the selected
option for many shut down facilities typically due to lack of ready cash, delay in dismantling may have serious disadvantages
such as loss of expertise and long term uncertainties.
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