Present: P. Bonneau, M. Bosteels, H. Burckhart, L. Feld, J. Godlewski, S.
Grohmann, G. Hallewell, R. Hammarstrom, A. Hervé, A. Placci, H. Postema, A.
Smith and V. Vacek.
 

Phase II
 

In response to a request from Hans Postema, Alain Herve explained why he
believed that two liquid cooling system prototypes will be necessary for the
Phase II tests. In addition to helping to eliminate scheduling difficulties,
the +15C coolant would not require the insulation needed for the -20C coolant
and hence would run in a different regime.

Michel presented in detail the proposed circuit for -25C tests with 5 KW
cooling power. C6F14 is the chosen coolant as it boils at 53C at atmospheric
pressure, has low viscosity at low temperature and has 25% of the heat
capacity of water. The first irradiation tests have been made on it with more
to follow. Michel asked about the size of the reservoir tank as it would cost
little to increase it from the planned 35 l to 50 l. He proposed to use a
circulator pump with a capacity of 5 m3/hr at 7 bar. Following comments from
the floor, he would add a particle filter in the return pipe to the reservoir
tank. It would be possible to place the heat exchanger either before or after
this tank. The refrigerator would work with R404 and be capable of going to
-30C. Although everything could be fitted into a standard rack it might be
preferable to have the controls in a separate rack. It was agreed that this
should be done. The PLC would be from Siemens (Schneider) or Telemechanique
with Alfredo believing that Schnieder was the preferred standard at the
moment. However Michel had no software for it though he would have for a
Telemechanique one. It was recognised that, whichever PLC was used, it would
not be identical to the final one.
The room temperature circuit was discussed and Jan stated that he wanted 12C
output from the heat exchanger to allow for heat entering the transfer lines
from power cables. This implied that a temperature even lower than 12C might
be necessary. Although this could be achieved using chilled water, it was
considered that this would be a pity as the standard mixed water supply would
be at 13C. The test system would have a cooling capacity of about 1.5 KW, but
this would be confirmed in one week’s time.
Cost estimates for the liquid cooling plants were 26 KCHF for the -20C one and
17 KCHF for the room temperature one. These cost estimates did not include
manpower nor did they include the cost of C6F14 at 100 CHF/l equivalent to 60
CHF/kg. Further costs would be incurred if chilled water connections had to be
made. The estimates did not include the transfer lines and distribution to the
test pieces.
CMS wished to have the -20C cooling plant installed for tests in B186 and Greg
had planned to have the ATLAS evaporative cooling tests carried out in LSS5.
However, he could foresee the need to have a combined test of evaporative
cooling pieces with a simulation of the heat shield cooled by liquid coolant,
which would require the two cooling plants to be installed close to each
other. The CMS members were not willing to have the evaporative cooling palnt
installed in B186 nor did they wish to carry out their cooling tests in LSS5.
However, they eventually agreed that ATLAS test pieces could undergo tests on
the cold liquid system in B186.
The Chairman’s impression was that the -20C system was becoming an almost
exclusively CMS system whereas the warm cooling system would be the fruit of a
close collaboration between ATLAS and CMS. This was confirmed after the
meeting when CMS volunteered to take responsibility for the -20C system and
are also willing to fund the room temperature system on their own. This would
appear to be a logical solution but ATLAS’s comments are still awaited.

A subgroup of those attending the meeting remained to discuss the evaporative
cooling tests. Phase I type tests will also be carried out on CF3I. Alasdair
explained that the first reaction of TIS to this fluid was that extra
precautions would need to be taken compared with CnFn+2 because of the
products from iodine irradiation. Capillaries were being studied as an
alternative to ruby injectors, the test set up in Michel’s lab having 2 out of
9 channels with blocked injectors.

There was a need to establish very soon the budgets for the Phase II tests as
work should already start on acquiring components. Michel wished manpower
needs for 1999 to be addressed.

 
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