nirex
Technical Report
Part 4
[Waste Inspection]
Prepared by
Mr. Sebastian Roberts
Mr. Tim Pegg
Mr. Sam Billing
Mr. Nick Petousis
Mr. Iain Hughes
Mr. Danny Thomas
Mr. Carl Young
Mr. Kevin Yong
Directed by
Dr. Phil Purnell
TABLE OF CONTENT
AIM
INTRODUCTION
1. WASTE INSPECTION
1.1. Inspection Cell’s Overall Function
1.2. METHODS OF INSPECTION
1.2.1. Direct Viewing and CCTVs
 Visual inspection can detect corrosion of packages, cracks and significant
deformation.
 Visual inspection also includes visual inspection of metal coupons welded on
packages.
 A crack width of at least 1mm can be detected by visual inspection, under
‘ideal’ condition, where adequate lighting and clean surface.
CCTV
mounted can
pan, tilt and
zoom.
Figure 1: A Radioactive Resistant Robotic Crawler with Mounted CCTV
Figure 2: Shielded Windows of a Hot Cell
ADVANTAGE
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Visual inspection is reliable. Sophisticated electronic sensors rely on batteries
and circuits. A small break down or malfunction in one of these two could
cause malfunction of the whole sensor.
Visual inspection doesn’t require much operational cost and maintenance cost
is relatively cheaper compared to other forms of inspection.
Visual inspection only requires maintenance on shielded windows, such as
cleaning and changing oil film.
Visual inspection could also be done in a ‘real-time’ basis. Instead of some
inspection methods which require time for computer or experiments to be
finished, visual inspection provides a direct output to the viewer.
DISADVANTAGE
 Visual inspection is somehow difficult to be implemented.
 Visual inspection could only be conducted with shielded windows
approximately 1.2m thick, or by mounting cameras on robotic crawlers.
 Visual inspection is often obstructed by blind spots or inaccessible of crawlers.
 Visual inspection is arguably not reliable for it is subjective and difficult to
compare results.
 Often permissible crack widths are often difficult to be observed by the eye.
 Shielded windows are also expensive and maintenance work is relatively
difficult to be conducted.
BEST PRACTICE
 Visual inspection should be done with adequate lighting. Hence adequate
lighting within the inspection cell must be available.
 It is also advisable that robotic crawlers to be equipped with lightings to allow
visual inspection to be conducted easily.
 CCTV should also be radioactive resistant and be able to zoom, pan and tilt.
This is to increase flexibility of cameras.
 Blind spots should be minimised through outlay of the inspection cell. Waste
monitoring within the vault however should allow access for robotic crawlers.
 It is best practice to be able to view the process of inspecting packages and
repackaging them via a shielded window. This could assure that all processes
are carried out smoothly.
1.2.2. 3D MAPPING
PRINCIPLES
 A 2D pattern of light stripes is projected onto the object.
 The light stripes will reflect off the object and reach the camera lens at
different angles due to the non-flat surface of the object.
 The pattern is imaged by means of a camera which is placed at an angle
relative to the light projector.
Figure 3: Schematic of 3D Mapping System
ACCURACY
 3D mapping has an accuracy of 1/1000, hence giving a crack detection of
approximately 1mm for 500L drums and 1.7mm for 3m3 packages.
 Can detect change in envelope dimensions of the package to approximately
1mm.
 crack detection is possible in that small areas of the drum can be zoomed in on
and mapped.(e.g. an area of 0.1x0.1m would detect changes in dimensions of
0.001mm)
What is the upper limit for the max allowable crack size before reworking is needed?
Table 1: Specifications of 3D Mapping Systems
Figure 4: Example of Comparison of a ‘Subsequent Map’ and a ‘Reference Map’, Indicating
Magnitude and forms of deformations
APPLICATION/ BEST PRACTICE
 As each package enters the PGRC for the first time, it will be mapped en route
to the storage vault. This will take place in the Inspection Cell of the target
vault. This will provide a ‘reference map’ of the package.
 After emplacement in the storage vault, each package will be taken to the
Inspection Cell at regular intervals during the 300 year monitoring period to be
mapped again. (e.g. approximately every 17 years if 1 unit* from each vault is
inspected each day).
 Subsequent maps will be compared to the reference map to note changes to the
envelope dimensions of a package over time.
* In the reference case, 1 unit* = 4x 500L drums/ 1x3m3 box/ 1x3m3 drum
VISUAL INSPECTION & 3D MAPPING METHOD
a)To map the sides of a package, the 3D mapping equipment will be located as in
Figure 5. The package will be rotated such that four sides are mapped.
Figure 5: 3D Mapping of the Sides of a Package
b)To map the top of the package, the 3D mapping equipment will move to the top
of the window.
Figure 6: 3D mapping of the Top of a Package
c)To map the base of the package, the 3D mapping equipment will move to the
base of the window and the package will be lifted.
Figure 7: 3D Mapping of the Base of a Package
1.2.3. CAPACITY (PACKAGES/DAY)
1.3. MINOR REWORKING
1.4. STANDARDS OR SPECIFICATIONS
REFERENCES
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General page - http://www.sintef.no/content/page1____6799.aspx
More detail http://www.sintef.no/upload/IKT/OpticalMeasurementSystems/Fact%20sheets/Str
uctured_Light_Factsheet.pdf
www.diakont.com/tv_prom.shtml
http://www.premiertechnology.cc
http://www.science.mcmaster.ca/mnr/Main-Page/Hotcell.htm