Detected tritium above drinking water standards near g2 ph

1
Update on Tritium Investigation Near g-2
Experiment

• Bet Zimmerman
• Environmental Services Division Manager
• Brookhaven Executive Roundtable
• Community Advisory Council
• December 1999

2
Summary

• BNLs Groundwater Protection Program includes
  enhanced groundwater monitoring
  
• Detected tritium above drinking water standards
  near g-2 physics experiment
  
• Source is g-2 activated soil shielding, leaching
  by rainwater
  
• Solution is to redesign experiment to reduce
  activation and install cap to prevent leaching
  
• No tritium in drinking water supplies

3
Groundwater Protection Program

• Relies on operational and engineered controls to
  prevent groundwater contamination
  
• Monitoring used to determine whether controls are
  effective and whether additional actions are
  needed
  
• BNL is installing over 80 new wells to monitor
  research and support facilities
  
• In early 1999, installed 4 new wells around the
  g-2 experiment to monitor potential soil
  activation areas
  

4
G-2 Physics Experiment
5
Existing Activated Soil Controls at V Target and
g-2 Beam Stop
Gunnite Cap Over g-2 Beam Stop
Rubber Membrane Over g-2 Target Cave
Paved Area Extends Underneath Target Hall And B
eam Stop
6
Groundwater Monitoring Results

• In November, tritium higher than drinking water
  standard seen at Well 054-067
  
• Launched investigation to
• Verify according to plan
• Characterize nature and extent of
  contamination
  
• Identify source
• Installed 18 Geoprobes, collected samples from
  various depths
  

7
Groundwater monitoring locations
8
Results

• Pencil-shaped plume 30 ft wide x 250 ft long
• Tritium (drinking water standard 20,000 pCi/L)
• 38 of 74 samples near or below detection limits
  for tritium
  
• Highest tritium concentration 1.8M pCi/L, 70 feet
  from source
  
• Sodium-22 (drinking water standard 400 pCi/L)
• 28 of 40 nondetect for sodium-22
• Highest sodium-22 concentration 60 pCi/L
• Tritium sodium-22 indicates soil activation
• Source is soil activation next to VQ12 magnet
  that is part of g-2 experiment
  
• Nearest BNL drinking water well monitored
  monthly--no tritium detected

9
Corrective Actions

• Tune particle beam to minimize soil activation.
  Monitor effectiveness.
  
• Continue groundwater monitoring.
• Model to ensure monitoring system is adequate.
• Installed expanded concrete cap to prevent
  rainwater from leaching activation products out
  of soil.

10
Activated Soil Near VQ12 Magnet
New Rain Barrier
.
.
.
Soil Shielding
.
Activated Soil
Beam re-tuned to reduce impact on VQ12 Magnet
Groundwater Table
EL 45
11
Conclusion

• Systematic approach identified a problem.
• Within weeks, Investigative Team determined
  extent of contamination and source, and BNL is
  fixing the problem.
  
• Tritium not threatening drinking water supply
• Tritium not expected to move offsite at
  detectable levels.
  
• In the future, possible that enhanced monitoring
  system may detect other problems.
  
• If this occurs, we will use monitoring data to
  help determine what corrective actions are
  needed.
  
• Must continue to work hard to control or
  eliminate pollution at the source in order to
  protect groundwater quality.