PSFC Diborane Installation/Deinstallation

Plasma Science and Fusion Center

Office of Environment, Safety, and Health

190 Albany Street, NW21 2nd floor
617-253-8440 (Catherine Fiore)
617-253-8917 (Matt Fulton)
617-253-5982 (Bill Byford)
617-258-5473 (Nancy Masley)
Fax 617-252-1808

Be Safe or Die

Procedure for Installation/Deinstallation of Diborane Gas

Author: Catherine L. Fiore, Chris Reddy, Joe Bosco

Version: Version 4.1 Released 5/23/06 by C. Fiore. Reviewed by J. Irby

Date: 11/1/99

Computer filename: /home/fiore/txt/www/]dibinst.html

System: Diborane Gas System

Person responsible: G. Dekow, C. Fiore, J. Irby

Introduction

It has been surmised that the most effective way to coat the walls of the Alcator C-Mod vacuum vessel with a thin layer of boron is to create a gaseous discharge in diborane gas inside the vacuum vessel. Diborane is highly toxic and flammable, and presents an explosion hazard. The gas delivery system must be of high integrity and leak free. Leak detection and remote control are essential. Procedures for handling, maintenance, process, and emergency response are required, as is training of any personnel directly or peripherally involved with using this material.

Scope/Purpose

This procedure is intended to ensure that the bottle is placed safely and securely into the system AND that the vacuum connections to the tokamak are verified to be free from leaks. Without that verification, the bottle is not permitted to remain in the cell.

This document covers the installation requirements for the diborane gas into the Alcator C-Mod Diborane facility. It describes how the diborane bottle is to be installed in the gas cabinet and also how it is to be removed from the facility.

Consequences of procedural failure

Failure to adequately test the diborane system could result in leakage of diborane gas into the cell or into the diborane housing, which could lead to fire or explosion, or to personnel exposure to toxic gas. Diborane is immediately dangerous to life and health at 40 ppm, and an explosion hazard at 9000 ppm.

Definitions

MDA-TLD-1-Gas monitor for the diborane system. One is located at the diborane gas cabinet. The other is located at B-port on the igloo, lower level. A spare backup unit is normally kept in Catherine Fiore's Office, NW21-203.
SCBA-Self Contained Breathing Apparatus. Two units are located at the entrance to the C-Mod power room, in the control room.

Responsibilities

Diborane Installation/Deinstallation will be overseen by the following people, all of whom are qualified to supervise this procedure:

Catherine Fiore,
Andy Pfeiffer,
Gary Dekow,
Bill Parkin,
Sam Pierson
Tom Toland

with the backup by members of the MIT Industrial Hygiene Office and the Cambridge Fire Department if necessary. Entry into the cell wearing SCBA is made by two SCBA qualified persons. Two other SCBA qualified persons must be standing by to provide emergency backup if needed.

These procedures will be reviewed and approved by a committee of no less than 3 knowledgeable persons, appointed by the Safety Officer.

Required Equipment

4 SCBA units
Helium sniffer
Wrenches for gas fittings and for the diborane bottle plug
Diagonal cutters for cutting the metal seal on the diborane bottle.
Walkie-talkies or cell phone

Assumptions and Prerequisites

The diborane system test procedure has been completed, and reviewed, and approval given for diborane gas installation.
The diborane has been delivered to the site, and is either at the loading dock or in the exterior toxic gas shed. In the case of deinstallation, it is assumed that it is already in the cell.
The SCBA units are checked and ready to use, and the installers have recently practiced wearing them (within the past 6 months.).
The walkie-talkie units have been checked, and are functional. Cell phones may be substituted for walkie-talkies.

Procedure

Installation

_____1.	If a total of 4 SCBA units are not available in the control room, borrow two units from the MIT Industrial Hygiene Office to have in the control room during the procedure.
_____2.	Move the helium leak sniffer to the cell and verify that it works.
_____3.	Before beginning installation of the diborane bottle, check that the diborane monitors are turned on and are operating correctly.
_____4.	Gather the tools necessary to open the plug and tighten the fittings.
_____5.	Obtain the key to the toxic gas shed and the key to the diborane cabinet.
_____6.	Have a total of 4 SCBA qualified persons on hand in the control room.
_____7.	Close the garage door on the cell.
_____8.	Clear and lock the labs adjacent to the cell (156A, 156B, 156C, 156D).
_____9.	Clear the cell of personnel, but do not place the cell in limited access.
____10.	Retrieve the gas bottle from the loading dock or toxic gas shed, and bring it to the cell.
____11.	Remove the plastic wrap around the valve if it was installed by the manufacturer.
____12.	Measure the bottle and adjust the height of the bottle stand in the gas cabinet accordingly.
____13.	Exit the cell, return to the control room, procure walkie-talkies or cell phones, and put on the SCBA.
____14.	Once the SCBA is hooked up and verified to be functioning correctly, re-enter the cell.
____15.	Remove the cap, and verify that the gas bottle valve is closed.
____16.	Open the cabinet and secure the gas bottle into place.
____17.	Cut the manufacturers seal if provided.
____18.	Disconnect the blocking plug.
____19.	Attach the diborane bottle to the CGA fitting provided for it and tighten the fitting.
____20.	Close the gas cabinet, and verify that no diborane reading is registering on the toxic gas monitors.
____21.	Lock the gas cabinet.
____22.	Notify the control room personnel that the installation is complete.
____23.	Exit the cell and remove the SCBA.
____24.	Post a sign at the door stating that the diborane has been installed in the cell.
____25.	Before returning the SCBA units to their housing, the installers should check the level of air in the gas bottles and change them if necessary.
____26.	Check the diborane gas bottle connection for leaks ____a. Bypass the cell access control input to the PLC in the power room. ____b. Open MV2 and the helium gas bottle valve if they are not already open. ____c. Verify that TR2 reads 30 to 35 PSI. ____d. Open PV5. ____e. Open PV4 ____f. Use the helium sniffer to check for helium leaks. ____g. Remove the jumper on the access control PLC in the power room.

If the leak check fails, the diborane bottle must be deinstalled.

Deinstallation

_____1.	If a total of 4 SCBA units are not available in the control room, borrow two units from the MIT Industrial Hygiene Office to have in the control room during the procedure.
_____2.	Gather the tools necessary to install the plug and loosen the fittings.
_____3.	Obtain the key to the toxic gas shed and the diborane cabinet.
_____4.	Search and lock the cell, power room,and diagnostic labs.
_____5.	Do a purge60 on the CRYBOR PLC.
_____6.	Have a total of 4 SCBA qualified persons on hand in the control room.
_____7.	Procure walkie talkies or cell phones.
_____8.	Put on the SCBA (the two deinstallers) and enter the cell.
_____9.	Verify that TR3 is reading zero.
____10.	Reaching through the cabinet window, make sure that the valve on the diborane bottle is closed.
____11.	Reaching through the cabinet window, undo the fitting.
____12.	If no diborane level is registered on the meter, unlock and open the cabinet and screw the plug into the gas bottle threads and tighten it.
____13.	Remove the bottle from the cabinet.
____14.	Cap the bottle.
____15.	Exit the cell and take the bottle to the loading dock area.
____16.	Exit the building and place the bottle in the toxic gas shed.
____17.	Relock the shed.
____18.	Remove the SCBA and return it to the control room.
____19.	Check the level of air in the SCBA bottles and change them if necessary.
____20.	Remove the sign at the door stating that the diborane has been installed in the cell.

Replacement

_____1.	If a total of 4 SCBA units are not available in the control room, borrow two units from the MIT Industrial Hygiene Office to have in the control room during the procedure.
_____2.	Move the helium leak sniffer to the cell and verify that it works.
_____3.	Check that the diborane monitors are turned on and are operating correctly.
_____4.	Gather the tools necessary to open the plug and tighten the fittings.
_____5.	Obtain the key to the toxic gas shed and the key to the diborane cabinet.
_____6.	Retrieve the gas bottle from the loading dock or toxic gas shed, and bring it to the gas hood in the vacuum lab.
_____7.	Remove the plastic wrap around the valve if it was installed by the manufacturer.
_____8.	Measure the bottle to see if adjustments to the bottle stand in the gas cabinet will be necessary.
_____9.	Search and lock the cell, power room,and diagnostic labs.
____10.	Do a purge60 on the CRYBOR PLC.
____11.	Have a total of 4 SCBA qualified persons on hand in the control room.
____12.	Procure walkie talkies or cell phones.
_____13.	Put on the SCBA (the two deinstallers), obtain the new diborane bottle from the vacuum lab and enter the cell.
_____14.	Secure the new bottle in the cell.
_____15.	Verify that TR3 is reading zero.
_____16.	Reaching through the cabinet window, make sure that the valve on the diborane bottle to be removed is closed.
_____17.	Reaching through the cabinet window, undo the fitting.
_____18.	If no diborane level is registered on the meter, unlock and open the cabinet and screw the plug into the gas bottle threads and tighten it.
_____19.	Remove the bottle from the cabinet.
_____20.	Cap the removed bottle and secure in the cell.
_____21.	If required, adjust the bottle stand.
____22.	Remove the cap from the new bottle, and verify that the gas bottle valve is closed.
____23.	Open the cabinet and secure the new gas bottle into place.
____24.	Cut the manufacturers seal if provided.
____25.	Disconnect the blocking plug.
____26.	Attach the new diborane bottle to the CGA fitting provided for it and tighten the fitting.
____27.	Close the gas cabinet, and verify that no diborane reading is registering on the toxic gas monitors.
____28.	Lock the gas cabinet.
____29.	Notify the control room personnel that the installation is complete.
____30.	Exit the cell with the removed diborane bottle and take the bottle to the loading dock area.
_____31.	Exit the building and place the bottle in the toxic gas shed.
_____32.	Relock the shed.
_____33.	Remove the SCBA and return it to the control room.
____34.	Verify all signs stating that the diborane has been installed in the cell are in place.
____35.	Before returning the SCBA units to their housing, the installers should check the level of air in the gas bottles and change them if necessary.
____36.	Check the diborane gas bottle connection for leaks ____a. Bypass the cell access control input to the PLC in the power room. ____b. Open MV2 and the helium gas bottle valve if they are not already open. ____c. Verify that TR2 reads 30 to 35 PSI. ____d. Open PV5. ____e. Open PV4 ____f. Use the helium sniffer to check for helium leaks. ____g. Remove the jumper on the access control PLC in the power room.

If the leak check fails, the bottle must be deinstalled and returned to the gas shed.

Training

Those responsible should review these procedures in detail, and should receive training in toxic gas hazards, and SCBA usage.

Cross references

Test Procedure for Diborane Gas System.
Procedure for Diborane Gas System Discharge Cleaning.
Procedure for Diborane Gas System Maintenance.
Emergency Procedure for Diborane Gas System.
Safety Analysis Report for Diborane Injection in Alcator C-Mod.

Distribution

E. Marmar, J. Irby, A. Pfeiffer, G. Dekow, R. Parkin, R. Clifford, J. Bosco, B. Childs

References

Matheson gas catalogue.
MDA Scientific `` TLD-1 Toxic Gas Detector Operating Instructions''

This page maintained by Catherine L. Fiore FIORE@PSFC.MIT.EDU