OverPressure Events at the Idaho National Engineering and Environmental Laboratory

1
 Over-Pressure Events at the Idaho National
Engineering and Environmental Laboratory

• James Wolski
• Department of Energy - Idaho Operations Office

May 13, 2003
2
Idaho National Engineering and Environmental
Laboratory Site

•  

      Glass flask rupture due to failed
pressure regulator gauge         Airline
rupture during dosimetry badge check        
Rupture of laboratory gas drying units        
Personnel injury resulting from failed
high-pressure fitting
3
GLASS FLASK RUPTURES DUE TO FAILED PRESSURE
REGULATOR GAUGE
4
GLASS FLASK RUPTURES DUE TO FAILED PRESSURE
REGULATOR GAUGE

• Background
• Event occurred at the Idaho Nuclear Technology
  and Engineering Center (INTEC)
• The activity in progress was to conduct a bubble
  leak test on a portable sample station
• The function of the sample station was to sample
  and purge underground spent nuclear fuel storage
  vaults
• The glass flask shattered sending shards over
  roughly a ten foot radius

5
GLASS FLASK RUPTURES DUE TO FAILED PRESSURE
REGULATOR GAUGE

• The sample station structural capability pressure
  had never been determined
• Bubble leak test was to be performed at 12 psi
• Rubber stopper on top of the glass flask came out
  during the test. Zip ties were used to hold the
  rubber stopper, but did not hold. A hose clamp
  was used to hold the rubber stopper
• An unusual whistling sound was noted coming out
  of the HEPA filter, but the test continued
• The glass flask shattered very shortly after
  passing the bubble leak test

6
GLASS FLASK RUPTURES DUE TO FAILED PRESSURE
REGULATOR GAUGE

• After the flask shattered, the system was
  modified to install a calibrated pressure
  indicator.
•  
• The regulator was used to pressurize the system.
  The regulator pressure gauge read 12 psi the
  calibrated gauge read 28 psi.
•  
• The pressure regulator pressure gauge was tested.
  The gauge read 10 psi with the test system
  pressure reading up to 100 psi.
•  
• Use of the glass flask in a pressurized system
  was not recommended by the flask manufacture.

7
GLASS FLASK RUPTURES DUE TO FAILED PRESSURE
REGULATOR GAUGE

•       No pressure relief protection was
  provided.
•  
•       No calibrated pressure indicator gauge was
  installed during the bubble leak testing.
•  
•       No maintenance inspection criteria or
  pre-operational check was provided for compressed
  gas regulators
•  
•       Company polices and procedures did not
  adequately implement appropriate compressed gas
  standards
•  

8
GLASS FLASK RUPTURES DUE TO FAILED PRESSURE
REGULATOR GAUGE

• Problems that contributed to the glass flask
  rupture
•       Personnel directing and performing work
  did not follow approved work control process
•       Workers failed to stop work when
  activities went beyond scope of work request
•       Workers continued to troubleshoot the
  cause and did not preserve the scene
•       The nitrogen regulator was tested and
  found to be defective causing over pressurization
  of the sample station
•       Calibrated gauge was not used to ensure
  correct system pressure was achieved

9

• AIR LINE RUPTURE DURING
•  
• DOSIMETRY BADGE CHECK

10
AIR LINE RUPTURE DURING DOSIMETRY BADGE CHECK

• Background
•  
•       Radiological and Environmental Laboratory
  at Central Facilities Area
•  
•       Air Operated Thermoluminescent Dosimeter
  Badge opening device
•  
•       System is operated with nitrogen pressure
  at 85 psig
•  
•       The pressurized tubing expanded and broke
  at normal operating pressure. One employee was
  treated for noise exposure

11
AIR LINE RUPTURE DURING DOSIMETRY BADGE CHECK

•       Badge opening station was relocated
•        Modifications were needed to the existing
  airline system
•        An under rated piece of ¼-inch tygon
  tubing was used, the tygon tubing was rated for
  60 pounds per square inch
•        The piece of tubing was selected based on
  the available length, rather than evaluating the
  pressure specifications of the tubing
•        A formal stop work was put in place
  pending a review of the incident

12
AIR LINE RUPTURE DURING DOSIMETRY BADGE CHECK

• Problems that contributed to the air line rupture
•        There was no configuration management
  system in place for this system
•       The employee did not use known pressure
  specifications to select the tubing used for the
  badge opening station
•       The piece of tubing was selected based on
  available length, rather than evaluating the
  pressure specifications of the tubing

13

• RUPTURE OF LABORATORY GAS
•  
• DRYING UNITS

14
RUPTURE OF LABORATORY GAS DRYING UNITS

•       The INEEL Research Center (IRC) is an R
  D Laboratory Facility for the Idaho National
  Engineering and Environmental Laboratory
•  
•       A researcher was switching an experiment
  in the laboratory from nitrogen to compressed air
•  
•       A system was established that used a new
  gas cylinder, a new pressure regulator and
  existing laboratory gas drying units
•  
•       After pressure was applied to the system,
  the drying units ruptured
•  
• Fragments, contents and parts from the
  drying units scattered throughout the laboratory.
  Three workers were injured

15
RUPTURE OF LABORATORY GAS DRYING UNITS

•       The system manual required a two-stage
  medium duty regulator, with a designed delivery
  range of 4-80 psig
•       The laboratory gas dryer units had a
  maximum working pressure of 90 psig
•  
•       The researcher selected a regulator that
  he believed was appropriate for the application
  from a regulator storage drawer
•  
•       He thought he had a two-stage regulator
  with a 0-300 psig delivery pressure gauge

16
RUPTURE OF LABORATORY GAS DRYING UNITS

• He actually had a 0-300 bar or 0-4000 psi single
  stage regulator with a designed delivery range of
  50-2500 psig, at high flow rates
• The cylinder valve was opened and there was no
  supply pressure gauge indication
•  
• The regulator T-handle was loosened and removed,
  later reinserted until some resistance was felt
•  
• The cylinder valve was opened, the system
  pressurized and the drying units ruptured

17
RUPTURE OF LABORATORY GAS DRYING UNITS

• Problems that resulted in the rupture of the
  drying units
•  
•       Improper regulator with defective supply
  pressure gauge was selected for the work to be
  performed
•  
•       Inappropriate adjustment of the regulator
  left at an unknown preset delivery pressure
•  
•       Compressed gas training courses did not
  contain sufficient information on hazards,
  lessons learned, relief valves, selection of
  regulators, maximum operating pressure and burst
  pressure
•  
•       The researcher was not familiar with the
  vendor manual or the appropriate procedure

18
PERSONNEL INJURY RESULTING  FROM FAILED  HIGH
PRESSURE FITTING
19
Personnel Injury Resulting From Failed High
Pressure Fitting

• An In Situ Grouting Treatability study was in
  progress at the Cold Test Pit South of the
  Radioactive Waste Management Complex (RWMC). The
  work was in a pit with buried simulated waste
  material.
• Activities taking place involved drilling and
  grouting of a series of holes in the Cold Test
  Pit.
• A Worker was struck in the right temple area by
  metal from a ruptured high-pressure fitting.
  There was a Type B accident investigation

20
Personnel Injury Resulting From Failed High
Pressure Fitting

• The high pressure pumping station consists of a
  positive displacement pump that was powered by a
  diesel engine through a gearbox and clutch.
•   
• The pumping station experienced problems with
  plugging.
•   
• A manual pressure relief on the pump was used to
  relieve pressure after the pump was secured.
•   
• The pump included an automatic pressure safety
  shutdown. The recommended setpoint was 290-435
  psi above operating pressure. The safety
  shutdown was set at 8700 psi.
•  
• No overpressure prevention device was provided
  downstream of the pump.

21
Personnel Injury Resulting From Failed High
Pressure Fitting

• The 45o swivel elbow that was replaced in the
  high-pressure grout line was designed in
  accordance with the SAE-J514 standard with a
  working pressure rating of 2500 psi
•   
• Normal system pressure was about 6000 psi
•  
• While using the grouting system, pressure
  was raised to establish flow. A fitting
  connecting the high pressure pump to a
  pressure/flow sensor failed, striking a
  subcontractor worker
•   
• The subcontractor did not communicate similar
  high-pressure failure of this system to MO
  contractor.

22
Personnel Injury Resulting From Failed High
Pressure Fitting

• Subcontractor process for the high-pressure
  grout system was inadequate. Parts were
  purchased and installed that did not meet system
  design.
•   
• MO contractor oversight of operations,
  maintenance and configuration management was
  inadequate.
•   
• Subcontractor did not follow and MO
  contractor did not adequately enforce the
  subcontract requirements.
•   
• DOE oversight of the project was inadequate

23

• Path forward
• INEEL Pressure Systems Task Team was established
• Developed a checklist for compressed gas
  assemblies to identify safety vulnerabilities
• Evaluated applicable systems, identified
  deficiencies, corrected deficiencies or took
  systems out of service
• Reviewed regulatory requirements, performed gap
  analysis
• Reviewed human performance contributing causes
  and error precursors
• Team proposed corrective actions, plan for
  site-wide implementation of immediate corrective
  actions until corrective actions are implemented