ASME Message

Abstracts
arrival signal for CH.1/CH.2 was 0.68 and 0.81 for CH.3/CH.2. Normalized amplitude attenuation model with a distance
was successfully obtained. The similarity of two signals were quantified using a mathematical tool called mean
magnitude squared coherence(MSC). The mean MSC between CH.1-CH.6, CH.2-CH.6, and CH.3-CH.6 are 0.8727,
0.9262 and 0.9040 respectively. The signal directly attached to the surface of a specimen presents the most similar
pattern with the applied source signal. While the signals from the epoxy filled waveguide show closer relationship with
the source than that without filling couplant. Additionally by using of system transfer function, the effect of waveguide is
apparently shown at the frequency of 118 kHz. The results derived from this study can be valuable information for the
quantitative analysis of signal processing in AE source localization and degree of crack damage in a radioactive waste
repository.
SESSION D7: D&D Poster
1) 40075 – Methods of Selected Input Calculation Data Verification And Their Influence On Decommissioning
Cost In the OMEGA Code
Frantisek Ondra. Vladimir Daniska, Ivan Rehak, Oto Schultz, DECONTA, a.s. (Slovakia);
Vladimir Necas, Slovak University of Technology in Bratislava (Slovakia)
The aim of this contribution is development of methodology for verification of selected input calculation data
(performance unit parameters, work group structure, and duration of time-dependent activities) of the OMEGA Code in
the individual PSL (Proposed Standardised List) structure parts. The OMEGA Code, developed by DECOM, a.s., is used
for calculation of nuclear power plant decommissioning parameters and decommissioning planning. The code represents
a complex tool modelling a real flow of materials and radioactivity in the whole process of decommissioning, beginning
from pre-dismantling decontamination and terminating with either final disposal of radioactive waste or release of
non-contaminated materials to the environment. The analytical methodology for evaluation of input data inaccuracy
impacting on calculation of cost and other output decommissioning parameters was developed. This methodology is
based on application of coefficients representing calculated cost relative change for contingency adjustment purpose. The
decommissioning process includes significant amount of various technical as well s administrative activities.
Decommissioning parameters calculation is performed by calculation procedures modelling these decommissioning
activities. The procedures use for calculation a lot of input and unit data. Decommissioning calculation parameters
projects having been performed using the OMEGA Code showed the necessity of development of a new verification
module. This module is able to display selected input data used for calculation for either specific inventory database item
or specific decommissioning activity in the PSL structure. The new verification module allows compare selected input
parameters to reference values including graphic display of differences. There is also a possibility to perform
recalculation of the some decommissioning option using reference values of input data and consequently to compare
calculated decommissioning data. These data (e.g. exposure, labor, and cost) and their differences can be compared both
in tables and graphs, for either specific inventory database item or specific PSL activity. The verification module within
the OMEGA Code brings a new view on impact of selected input data change on calculated decommissioning data. It is
auxiliary tool for contingency calculation using analytical methods developed last year.
2) 40126 – Detailed Standardized Decommissioning Parameters Calculation for Larger echnological Aggregates
and Relevant Buildings in Nuclear Power Plants using the OMEGA Code
Peter Bezak, Vladimir Daniska, DECONTA, a.s. (Slovakia); Ivan Rehak, DECOM, a.s. (Slovakia)
Computer code OMEGA, developed by DECOM a.s., is used for evaluation of nuclear facility decommissioning
activities. The Code implements in full extent the standardised cost structure PSL. Decommissioning activities of nuclear
facility are involved in compact calculation structure. Calculation models a real material and radioactivity flow and
reflects a radioactivity decay during decommissioning process. Calculation processes material items, which are linked to
decommissioning procedures (dismantling, demolition and decontamination procedures) in calculation structure.
Inventory database contains approx 90 standard material items of technological equipment (pipes, valves, tanks etc.),
approx 50 specific items (pieces, planked components etc.). The inventory database also contains 14 building categories
(masonry, concrete, steel construction etc.). A new task is costing the larger technological aggregates decommissioning
in nuclear power plants. The paper introduces development of larger technological aggregates inventory database. These
aggregates include: 1. Reactor and its internals 2. Steam generator 3. Pressurizer 4. Refueling machine, etc.. Larger
technological aggregates decommissioning activities need to be implemented into decommissioning planning and costing
Code OMEGA. So decommissioning procedures representing these activities have to be developed for technological
aggregates, and dismantling unit factors need to be set up as well. A proper definition of dismantling techniques and
workgroups performing the techniques is also important, taking into account presence of activated and contaminated
materials to be dismantled. Where a dose rate is higher than a limit for manual dismantling, remote dismantling
techniques are applied. Paper introduces manual and remote techniques available for larger technological aggregates
dismantling. Dismantling procedures of larger technological aggregates are based on reversed sequence of their
commissioning. The paper also deals with specific dismantling procedures, when equipment is dismantled as a whole and
moved to a fragmentation facility. There it will be fragmented to smaller parts, put into containers for disposal in
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