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Brunswick Nuclear Plant Storm Drain Stabilization Pond Tritium Issues. BNP SDSP. BNP SDSP. History. 1977 - Stabilization Pond constructed from a spoil pond to provide Brunswick Nuclear Plant (BNP) with the capability to meet EPA effluent storm water release standards - PowerPoint PPT Presentation
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Brunswick Nuclear Plant Storm Drain Stabilization Pond
Tritium Issues
BNP SDSPBNP SDSP
History
1977 - Stabilization Pond constructed from a spoil pond to provide Brunswick Nuclear Plant (BNP) with the capability to meet EPA effluent storm water release standards
1983 - Issuance of RETS. Stabilization Pond identified as a potential liquid effluent release point.
1992 - The licensee identified the Stabilization Pond as a previously unrecognized release point for tritium.
History
1997 - ANI Inspection Report In as much as the pond is unlined, the
likelihood of nuclide migration (particularly tritium) into the groundwater is relatively high.
History
2006 – BNP began to analyze water in manholes for tritium and gamma emitters
2007 - Tritium was discovered in manholes in vicinity of Storm Drain Stabilization Pond Values were 75,000 pCi/l to 150,000 pCi/l
2007 Standing/Flowing water containing tritium was found on the areas outside of the SDSP dike some of which was flowing toward intake canal. Values were 47,000 pCi/l to 880,000 pCi/l
.
History
As part of the expanded monitoring scope, resulting from the discovery of tritium in waters outside of the SDSP, more samples were taken and analyzed at various locations in and around the SDSP area.
Monitoring Wells installed at SDSP area.
MH < LLD
< LLD (Well)
MH < LLD
MH 76,210
MH166,800
336,800
47,450
804,100
WP-24<LLD
793,600 882,400
330,900
342,400
< LLD (well)
565,200 286,500391,200
281,600
604,500
36,050
197,400
93,410
180,400
607,200
1,511,000
BNP SDSPManhole and Surface Water Results June 2007
WP-48 (612)
WP-49 (409)WP-50 (413)
WP-51 (411)
WP-52 ND
WP-57 ND
WP-56 ND
WP-55 ND WP-54 NDWP-53 ND
WP-26 (281,600)
GUM LOG BRANCH
NANCY CREEK
WALDEN’S CREEK
WP-27 (36,050) RECOVERY POND
Expanded View of SDSP Area
ESS - 20 B & C
Well(s) Complete
ESS - 19 B & C
ESS - 22 B & C
ESS - 21 B & C
ESS - 24 A, B & C
Monitoring Wells
ESS - 23 C
ESS - 18 B & C
ESS – 17A, B & C
Stab Well
ESS - 25 B
ESS - 26 C
ESS – 27A & CESS - 28 C
ESS-NC-1
ESS-NC-2
ESS-NC-3
ESS-NC-4 ESS-NC-5 ESS-GLB-1
ESS - 25 C
ESS - 31 C
ESS - 30 C
Summary of Results
Highest activity taken in shallow wells was ~750,000 p/Ci/L.
Highest activity taken in intermediate wells was ~24,000 p/Ci/L.
Activity was not detected in deep wells.
Immediate/ Interim Corrective Actions
Reduced the primary input source of tritium to the SDSP Terminated unmonitored releases into the intake canal – instituted
compensatory measures Installed catch basins to route groundwater flow to the SDSP Installed hard pipe arrangement to release SDSP water to intake
canal versus open ditch Made voluntary notifications to government officials and the
community Installed new ground water monitoring wells around perimeter of
SDSP Performed a complete sample profile of the surface and
groundwater at locations around the perimeter of the stabilization pond to define the extent and magnitude of tritium activity
Planned Corrective Actions
Develop and implement a plant modification to stop major input source
Remediate Pond and Groundwater Conduct a full dose assessment of the impact to the
public Evaluate other potential areas/structures outside the
protected area that may exhibit the same characteristics or susceptibility to leakage (extent of condition/cause).
Install additional monitoring wells
Off-site Detections in Surface Water
Off-site Detections in Surface Water
Off-site Detections in Surface Water
Off-site Detections in Surface Water
Off-site Detections in Surface Water
Other Tritium Related Issues
SDSP tritium evaporation Accounted for approximately 74 curies in 2007 which yielded
approximately 2E-02 mrem inhalation dose to the nearest resident.
Model for transpiration still under development.
Liquid releases from marsh areas Marsh area releases are to Nancy's Creek Accounted for approximately 55 curies of tritium which yielded a
calculated dose of approximately 7.2E-04 mrem dose from fish consumption and 1.8E-04 mrem from invertebrates consumption (shrimp, crabs, etc.).
Methodology still under development for additional refinement relating to marsh and aquifer releases to surface water.
Planned Future Actions
Focused Groundwater Extraction with Containment and MNA to achieve the RAOs.
Establish a tritium fade and transport model to refine dose calculations.
Establish transpiration model for airborne dose modeling.
Questions