%0 Journal Article
%A Tatsumoto, H.
%A Lyngh, D.
%A Lee, Y.
%A Hartl, M.
%A Sina, H.
%A Beßler, Y.
%A Kobayashi, H.
%A Sakamoto, Y.
%A Hasegawa, T.
%T Design of an in-situ measurement system for ortho and para liquid hydrogen fractions at ESS
%J IOP conference series / Materials science and engineering
%V 1240
%N 1
%@ 1757-8981
%C London [u.a.]
%I Institute of Physics
%M FZJ-2023-01673
%P 012117 -
%D 2022
%X The Cryogenic Moderator System (CMS) is equipped with a catalyst to convert hydrogen from the ortho state to the para state, to keep desirably high parahydrogen fractions in the cold moderators, which is required to deliver a high brightness cold neutron beams to the scientific instruments using neutron scattering. An in-situ measurement system for the ortho and para fractions of liquid hydrogen (OPMS) where a Raman spectroscopy will be used is being developed. The required measurement precision is 0.1% to detect an undesirable shift towards a high orthohydrogen fraction caused by neutron scattering driven para-to-ortho back conversion. The dedicated OPMS sampling line has been designed and is placed in a bypass line from and to the CMS to minimize the hydrogen inventory and to make it physically isolated from the CMS if a sapphire window failure happens. Accident analysis for a hydrogen leak due to the sapphire window failure was carried out using an inhouse-developed simulation code, and the required safety relief size has been determined.
%F PUB:(DE-HGF)16
%9 Journal Article
%R 10.1088/1757-899X/1240/1/012117
%U https://juser.fz-juelich.de/record/1006439