Frank Laboratory of Neutron Physics

Joint Laboratory Seminar

Leader – Shvetsov V.N.

Date and Time: Thursday, 8 April 2021, at 11:00 AM

Venue: Online seminar on Webex, Frank Laboratory of Neutron Physics

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Seminar topic: «Current status of the development and operation of a suite of IBR-2 cryogenic moderators in 2012-2020»

Speaker: K. A. Mukhin

Abstract:

In 2012, tests of CM-202 (first stage of the suite of IBR-2 cryogenic moderators) began in the trial operation mode at power. The CM-202 in the cryogenic mode for physics experiments has operated for more than 4500 h. During this time, data on the change in the viscosity of the moderator material under irradiation and empirical quantitative values of released radiolytic hydrogen were obtained, the cryogenic cooling system of the suite was upgraded, and neutron-physical data for cryogenic moderators (CM) were collected during their operation in different temperature modes.

In December 2020, in the trial operation mode, the CM-201 central direction moderator (beamlines 1, 4, 5, 6, 9) operated in the cryogenic regime for physics experiments for the first time.

The report will provide a brief overview of the operation of the suite of IBR-2 cryogenic moderators from 2012 to 2021. The evaluation of the efficiency and reliability of technological equipment of the CM suite in various operation modes is given. Comparative characteristics of the viscosity, hydrogen yield, and temperature modes of operation of CM-201 and CM-202 are presented, taking into account their different geometry of the working chambers and different location of the cryogenic chambers relative to the reactor core. Basing on the results of the work for this period, spectra of the neutron flux of the beams in the thermal and cold modes, plans for the development of the CM suite, the structure of the commissioning group, number of personnel and necessary resources for putting the CM suite into operation will be presented.