With some difficulty.
This weld was actually made in a mock-up. It was made through a 12-centimetre opening some 30 feet away from the actual plate. This sample is made of ethyl material that is the thickness and the curvature of the vessel. This was actually done on November 15, mid-November. This was a test weld.
We went to the vessel and did the first repair on December 12. Through December, we completed a total of five repair sites and they went very well.
We believed the process would continue with the learning and that we would be able to get more efficient at doing these repairs as we progressed through the more difficult sites. That actually was not what occurred.
I don't know if you can see the back of the plate, but we've actually machined these samples to replicate the corrosion in the vessel. From all of the inspection we've done, we have a very accurate model of the corrosion in the vessel, so these plates have been machined to exactly replicate that. You can see this area.
This repair required changing technique because of the stress on the vessel, and this what is taking the additional time. In this case, we've actually had to add structural plates. This is not complete, by the way; this was a sample in process. These plates are actually structural and they're welded in with fillet welds around the plate before we move to weld buildup. I point out that these are nuclear-grade material. The welds and weld procedures are using nuclear-grade material and being done to nuclear standards.
Having put the plates in place on that repair site—and by the way, that is the site that is actually being repaired as we speak; we're actually doing this repair today—in the final repair, we have the plates and then we apply weld buildup below, above, and on both sides to complete the repair process. I would point out that you can probably see, even at a distance, that there is a significant amount of deformation in the sample plate. That is why we had to go to this type of a repair in order to reduce the stress on the vessel. It's the development of this that has taken significant time. On this plate, there are a number of defects. This was plate number 9. In fact, we produced 30 of these samples in order to be prepared to go in the vessel and complete the weld that we're doing today.
Finally, regarding the last site, if you look at the corrosion here, it actually stretches from end to end. This is the largest site. The area that is deeply corroded, with less than a millimetre of vessel wall remaining, is quite large in this area. For this repair—and this is not complete—we have completed the design, and it will involve nine thicker structural plates. Then we'll have to develop specific weld procedures—because these plates are spaced differently than the ones in the last sample—to in fact do the structural welds around the plates. Then we will, in similar fashion, build up below, above, and all the way across in order to cover the area of corrosion.
This is the job that lies ahead, and again, all of this meets nuclear standards. The repair is done by authorized authorities that carry certificates to do this type of repair, and all of the materials are nuclear materials. This will be inspected to meet all of the requirements for the vessel and will be accepted by the regulator when it's done. This will give us a lasting repair.