Date: Fri, 29 Sep 2000 15:07:40 -0500 From: Jim Kilmer To: Greg Bock , Jim Hylen , Dave Pushka Cc: Craig Moore , David B. Augustine , Ernie Villegas , Jim Kilmer , Pat Hurh , Paul Czarapata Subject: Comments on Minos target pile Gentlemen, Here are my comments on the review. I've also appended all of the comments from the other members of the team. Jim Kilmer's list: 1. How do you grab a T block remotely with the crane? Needs to be done in a radiation field later. 2. I don't understand how T blocks are installed under transverse beams. Write-up stated they were installed before carriage went in. Then how does the horn get past them? 3. Should green and blue blocks standing on edge be tack welded together to ensure stability of the structure? 4. What supports the helium tubes? Do they have to be removed (or moved) to get out a horn? 5. I'm worried about the air cooling flow rate in the chase too. Note that from Dave's talk if you consider the clear flow area cross-section you get 71 mph and not 30 mph. 6. A concern was raised in the meeting about methods required to keep crane controls functioning in the high radiation field. Think NM2. 7. It was mentioned that H blocks might have to be purchased. Two items are noted. a) If blocks are purchased try to get low sodium concrete blocks. b) We used a large number of H blocks in HIL for E-872. 8. There was discussion about whether the present location of the prototype horn would be available for future horn work. This should be sorted out quickly by Beams Division and for the life of the experiment. Paul Czarapata's list: Actually I think you had them in your comments. i.e. An instrumentation/electrical engineer should be brought into the game now so that any instrumentation that is desired can be incorporated now and not have to be "kludged" on to the final product. Issues such as cable routing, sensor mounting etc. should be handled up front. Paul Dave Augustine's list: My main concern was the tunnel temp, humidity ,and wet floors. At that elevation water will slowly leach into the tunnel. Air flow must be enough to evaporate it. De-humidifiers must be enough to dry the air to a reasonable level, 50%. Hugh amounts of new air is introduced into the tunnel to cool the shield steel. A paddle wheel type de-humidified is planned. I am assuming that the 100 degree waste heat is being dumped into the tunnel for heat as well. Ernie Villegas' list: Just a few notes concerning the Numi target pile review. 1) From the point of view of a first time observer, the design seems well beyond the conceptual stage. Still,there is a great deal of engineering/design/fabrication work that has to be completed within the next two years. I would question whether enough manpower allocations have been made to this area. In particular I was surprised to hear that electrical engineering has not been involved to date. 2) Power connections to the horns(striplines?) do not seem to be well define. 3) The work required to finalize the controls for the modules is just begging for engineering support. 4) Given the lack of dimensional precision and weight (10 tons) for the shielding steel blocks, has Enough manpower been devoted to this task? Five per day seems fine at first glance, but maybe a closer look would indicate a slower rate of progress. Pat Hurh's list Here's a summary of my comments from the review: General: Overall, I see no major holes or 'show-stoppers' in the plans presented. It should be noted that the plans presented were conceptual designs with only portions of detailed design complete. There are several issues that require detailed engineering and designing, but overall the concepts presented seem sound. I think the only general concern that I have is the amount of manpower and other resources that are required to complete the Target Hall on schedule. It is clear that additional engineering, drafting, and technician support is needed to complete the detailed work successfully on schedule. Specific: Some details that need significant attention: 1) Chase Shielding Installation - The geometrical tolerances of the Duratek steel blocks are large enough to require individual shimming, fitting, and grouting of each block. Because of the weight and numbers of blocks required and the deep locale of the target hall, installation will be a major project by itself. Blocks should probably be measured and classified into tolerance groups ahead of installation to ease selection and fitting. Blocks can also be classified according to chemical content so that blocks undesirable for radiological reasons can be placed in locations of least impact. Mechanisms and devices to tow the blocks from the shaft to the chase must also be carefully developed. 2) Target Hall Access Procedures - Although detailed procedures cannot readily be produced for Target Hall accesses (i.e. to change a horn location), general procedures which outline the steps involved for major accesses should be developed now. These procedures will help engineers and designers visualize how their designs will be utilized in practice and ensure that enough flexibility in the Target Hall design is provided to accommodate needed tasks. Special attention should be paid to the musical chairs game that will be played with filler tee-blocks and modules. 3) Alignment of Target Hall components - Although absolute placement of the components can be done to the given tolerances (.020" ) initially, over time the alignment may shift out of tolerance due to thermal expansion/contraction and mechanical backlash/hysteresis. The thermally hot areas (especially at Horn 1 module) should be looked at carefully to see how they affect alignment of the components. Cooling and/or thermally isolating the Horn 1 support shafts should be considered to minimize vertical thermal motion of the Horn. A strung wire system with capacitive pick-ups looks like a promising idea to provide absolute referencing of the components over time (esp. horizontally). 4) HVAC - The plan presented seemed feasible to cool the shielding blocks and keep the poured concrete thermally stable. The high air velocities in the chase seem surprising, but theoretically doable. In practice, engineers and designers must be careful to make sure that additional loadings on all components in the Target Chase are taken into account. Small instrumentation wires and other non-rigid structures could see extreme buffeting from the 32 mph winds predicted. Installation workers also must be careful to ensure that all air leaks are minimized (ensure flow through chase) and that channels between concrete and steel (especially at the bottom) remain clear and free. During operation failure of the sump system may mean that the lower air passages could be blocked with water (?) this should probably be looked at. The actual ducting and HVAC equipment has not yet been finalized. Obviously care must be taken in order to make sure the resulting system is easily configured and balanced for the as built geometries. In addition, a system to collect and test condensate for irradiation must be developed and implemented. 5) Hot Work Cell Equipment - Lift tables, shielding issues and remote manipulation issues must be addressed for this area. It is important to predict what operations can be done and can't be done using this facility so that engineers and designers don't just assume that some task can be done in the Hot Work Cell. 6) Flexible Stripline Joint - Although this probably isn't technically part of the review panel's charge, it looks like the biggest technical unknown at this time. Engineering resources should be brought to bear as soon as possible on this problem. A possible 'plan B' described during the review was to move the entire stripline module with the horn. I don't think that is a particularly attractive idea because of the loads placed on the horn support. I think a possible back-up plan would be to automate the stripline hard connection at the bottom of the module so that when the horn is moved the joint is loose. However, welding of the connection under many high current pulses could complicate that mechanism. 7) Instrumentation and Controls - There seemed to be a lack of information about sensing devices and control systems for the various motion devices. Electrical Engineering support should be added to address these issues at this time. It is preferable to have these issues settled early so that accommodation of the needed devices can be made by the mechanical designers. Craig Moore's list: , These are some of the concerns/issues that I have from the review: The question of the relative alignment of the devices once they are out of sight. If a beam based alignment scheme can be used in a relatively straightforward way without a great deal of time, then a lot of my concern is obviated, and there is probably enough steering to hit the center line of the elements if they are on a line. However being able to remotely monitor the relative motion of the objects while the temperature us changing could be very useful (and reassuring). It is clear that the horizontal motion is of the most concern. At the least, being able to check the elements by using removable plugs in the shielding seems a good idea; and at the most, having a remote readout system based on stretched wire techniques, laser techniques, or other techniques would be ideal. I understand that the force of the 30 m.p.h. air flowing down the chase is not much but I would still worry about turbulence and the inducement of normal mode oscillation of the hanging elements. The question of neutron leakage through the uneven blue/green blocks needs to be looked at. If additional concrete shielding blocks need to be purchased then finding out how much extra it would cost for low sodium concrete would be useful.