Sunday, November 18, 2007

Fond Memories from 2004

In addition to work we carried out within the Big Rock Point containment sphere (the 'green ball') which led to the removal and transportation of the reactor vessel - see earlier post, we also did work outside. Below is a little summary I put together back in 2004 concerning the demolition of the 240' high stack and the commencement of the demolition activity. The reason we demolished the stack in the manner we did as opposed to a conventional explosive approach was the concern with internal stack radiological contamination. To decontaminate while in situ was considered to be too much of a risk so sectioning was employed with decontamination work taking place once the stack sections were placed on the ground.

The Big Rock Point Off Gas Stack Continues to Deny Us Until!

Thursday, October 9th 2004, 06:60 in the morning and once again the weather forecast was not good. As all the websites had stated the night before the wind speed was going to be too high. By our imposed safety criterion 15mph is the wind speed limit, and that is in the elevated man basket, not on the ground that must not be exceeded to enable work to occur on the stack.

The Man-Basket suspended of the man-lift crane with the 350’ Manitowoc standing by next to the 240’ Big Rock Off-Stack prior to demolition efforts.

We walked across to Bierlein’s trailer and discussed the plan for the weekend. A little down in the dumps as we had seemed to be having this type of discussion for the past week which at this moment seemed like a lifetime and tomorrow didn’t look good either.

Both Cranes look impressive next to the Big Rock Sphere and Turbine Building– alas all is now gone but that’s what we were there to do.

Saturday evening holds a promise, no, we all decided, keeping people in the area over the weekend was not the thing to do, especially with the track record we had with the wind predictions previously. So there we had it, no weekend work but we would commence an evening campaign starting Monday October 11th because previous week had shown us that after around 5 pm the wind dropped considerably.

Kevin and I 240’ above Terra firma (my favorite place)

I went back to my office and became distracted by other things but every so often the little nagging thought of when are we going to get this stack down, especially the first piece? Pictures of blizzards popped up in mind and I would rack my brain and try and recall the previous 4 years of Michigan Octobers I had experienced. In a vain attempt to keep up hope maybe mistakenly I recalled beautifully sunny and calm, but cold, days where I had ridden my motorcycle – we should be good.

A site not often seen – the Sphere from the top of the stack with the Lake Michigan coast line.

Lunchtime arrived and went then I got a call from Lonnie Taylor, BNFL’s stack demolition supervisor, “we’re going up Mick, the winds down” Wow, what a surprise, all websites throughout the morning stated that the ground wind speed would be greater than 10 mph meaning the elevated wind speeds would probably be approaching 20 mph!

Outside I went and that beautiful yellow man basket was at the top of the stack with Gary Nye and Dave Rice of Bierlein commencing the hammering of the lifting holes in the first section. I thought to myself, great, if we can just get those two holes done today that will be a great start for next week.

Big Rock Point taken as we flew down the side of Lake Michigan

Well, the weather held with us, the holes were done by 3:00 pm and the guys took a break and up they went again. That beautiful hammering sound continued into the early evening, the flags on the top of the crane would blow a bit and then settle again. The hammering continued and then stop briefly as Gary and Dave would insert another wooden wedge, 3 feet away from the previously installed one, to ensure that the portion of stack remained stable with the ever increasing concrete cut being made. The hammering would start again and darkness arrived. Another well deserved brief break was taken; the floodlights were lit and up and off again went the guys, back to their work place in the sky.

As the hammering continued Ed Cheeney, the head of the camera crew who make a lot of Consumers promotional films, was telling me about his experiences when he filmed in the Middle East and Africa, covering such historic events like the elections in Rhodesia just before it became Zimbabwe in 1980. Wow, names sprang into my mind like Ian Smith, the ‘last of the White Rulers’ and Robert Mugabe, the leader of the Zimbabwe African National Union (ZANU) who became and still is the president, who were big news throughout my childhood, not to mention Davis Livingston, the Scottish explorer who was the first white man to arrive in the area back in 1851. We continue our interesting discussion and reminisce as the evening draws to a close. At 09:30 pm, Gary and Dave, who have now been at it for almost 8 hours, call it a day. Both of the lifting holes have been made, the lifting crane was attached and approximately 70% of the separation cut has been made. Well done guys, what a finish to a day that when we all walked in approximately 15 hours earlier nobody had any expectation of doing anything on that stack and here we were.

We all depart to our differing locations because it is a scheduled 4 day weekend and take a well deserved rest until Monday afternoon, when we have planned to return to finally separate and lower the first section to the ground.

A view across towards Wisconsin

Five o’clock in the afternoon arrives. The weather is good, hardly no wind and everyone is ready to start. That magical sound of a jack hammer knocking into the stack concrete rings in my ears once again, such sweet music and then we get the call, the last piece of concrete has been removed we’re ready to burn out the rebar. The crane takes some of the load, as per the plan, and the burning commences, we’re getting close, as the rebar is cut the crane takes the full load, everyone is starting to get excited. Just as 9:00 pm passes the section gently swings free, clears the stack and the lowering commences. Before we know it it’s on the floor, “wow, that came down sweetly” Lonnie states. It is 9:20 pm in the evening and we all congratulate each other on achieving another successful step towards completing the Big Rock Point Restoration Project.

Update – We actually completed the total demolition of the stack in two months almost a month ahead of schedule. It was demolished by cutting the stack up into sections weighing no more than 40,000 lb, lowering each piece to the ground, decontaminating each of the sections until cleared for free release. Each section was then crushed with a wrecking ball prior to shipment off site and disposal as concrete rubble. Some pictures below show different stages of the work.

The photograph below depicts clearly the cut line adjacent to the man-basket with the final re-bar cutting taking place. Thereafter the piece (#12 of 15) was removed and placed at another location on the site for decontamination work. (You can see just below the orange line marking where the next cut will be made)

A very dramatic picture showing the shower of sparks as one of the re-bar sections is cut. If you look closely you can see the wooden wedges that were used to keep the stack section stable during the concrete removal, jack hammering, operations.

The section above is carefully lifted clear then lowered to the ground.

If you look carefully at the upper center area of the lower picture you can discern some of the removed stack sections laying on their sides.

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