Description of the Ortho-to-Para Convertor and Internal Plumbing of the Hydrogen Target

Transcription

1 Description of the Ortho-to-Para Convertor and Internal Plumbing of the Hydrogen Target Prepared: M. Snow, Indiana University, March 08, 2011 Checked : H. Nann, Indiana University, October 25, 2011 Approved: S. Penttila, ORNL, October 25, 2011 William Snow Digitally signed by William Snow DN: cn=william Snow, o=ceem, ou=indiana University, =wsnow@indiana.edu, c=us Date: :58:13-04'00' Hermann Nann Digitally signed by Hermann Nann DN: cn=hermann Nann, o=indiana University, ou=ceem, =nann@indiana.edu, c=us Date: :27:36-05'00' 1. Scope This document addresses the design of the ortho-to-para convertor and internal hydrogen target plumbing that connects to the hydrogen fill/vent line which is part of the safety hydrogen relief system of the NPDGamma liquid hydrogen target. 2. Components covered The document covers the ortho-to-para convertor, the hydrogen liquefaction chamber, and the plumbing connections of the target vessel to the fill/vent line. see Fig. 1 and 2. Figure 1. A model view of the target vessel, liquefaction chamber, OPC, and interconned pluming. The white shell is a 6Li loaded neutron absorber which will cover the components.

2 Fill/vent line connection AL/SS friction welds Hydrogen liquefaction chamber Recirculation loop connection Ortho-to- Para convertor Figure 1. A cut view of the hydrogen target plumbing and OPC. 3. Description The hydrogen gas enters the system through the 1.5 OD stainless steel fill/vent line connection. After the tube bends it forks into 2 paths. One path takes the gas directly into the top of the aluminum target vessel with a 1.5 OD stainless steel line connected using a friction weld. The other goes through a ¼ OD stainless steel tube into a copper hydrogen liquefaction chamber. Figure 3 shows the tube between the fill/vent line and the Conflat flange. This tube has a 1.33 Conflat joint in the middle with a strengthening ring to increase the sealing force on the joint. The SS tube is soldered into the copper liquefaction chamber using Castolin silver solder: all other SS tube joints are welded. The liquefaction chamber is directly attached to the upper cryorefrigerator and possesses internal grooves (see Fig. 4) to increase the surface area of contact for the cold H 2 gas, The liquid hydrogen drips down a 3/8 OD stainless steel tube (also soldered into the chamber) soldered into the bottom of the liquefaction chamber (see Fig 4) and flows into the copper ortho-to-para convertor. The ortho-to-para convertor

3 (OPC, Fig. 6) contains the iron oxide catalyst powder confined inside the copper chamber using stainless steel mesh wire on the inlet and outlets. The ortho-topara convertor employs brazed connections and its outlet is a ½ OD stainless tube connected to an ¾ OD aluminum tube at the bottom of the target vessel through another friction weld joint. Figure 3: Part of connection path of fill/vent line to the hydrogen liquefaction chamber.

4 Figure 4: Top piece of the hydrogen liquefaction chamber. Figure 5: Cut view of the bottom portion of the hydrogen liquefaction chamber.

5 Figure 6: Vertical cut view of the ortho-to-para convertor. 4. Testing In addition to the general requirements, this section of the fill/vent line must in addition be able to withstand several thermal cycles over the course of the experiment between room temperature and 17K. The hydrogen liquefaction chamber and the tubing that connects it to the OPC and the fill/vent line were used in the LANSCE experiment and therefore subjected to several cooldowns, liquid hydrogen fills, and liquid hydrogen venting events. Extensive testing has been conducted on the friction weld joints (documented in ThermalCyclingBimetalJointFINAL.pdf), the conflat flanges (documented in IUCFtestsofCFflanges2copy.pdf), and the brazed joints of the ortho-to-para convertor (described in. and rtervacuumbrazing/). All of these documents can be found on the website for the liquid hydrogen target.