1 Issues for the Tank Waste Committee Hanford Advisorary Board October 10, 2006.
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Transcript of 1 Issues for the Tank Waste Committee Hanford Advisorary Board October 10, 2006.
1
Issues for the Tank Waste CommitteeHanford Advisorary Board
October 10, 2006
2
Inadequate Characterization/Groundwater Issues
• Ongoing degradation of groundwater due to past tank leaks, absence of RCRA Corrective Action
• Groundwater contamination has yet to be officially attributed to an Individual tank leak
• None of the larger tank leaks have been adequately characterized
• Soil samples have not been acquired in any of the areas with ongoing migration of radionuclides
• Questionable estimates of past tank leaks (RPP-23405)
3
Tank Farms located in 200 East(Figure from DOE/ORP-2005-1)
4
Ongoing degradation of groundwater due to past tank leaks
Groundwater Conditions Underneath Single-Shell Tank Farms in 200 East
0
2000
4000
6000
8000
10000
12000
14000
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
Time
Max
imu
m T
c-99
pC
i/L
A-AX WMA
B-BX-BY WMA
C WMA
Drinking Water Standard = 900 pCi/L
5
Handbook of Groundwater Protection and Cleanup Policies for RCRA Corrective Action
EPA530-R-04-030
6
PNNL Annual Groundwater MonitoringB-BX-BY WMA and Surrounding Waste Sites
1995 through 2000
• Five year gap in the mapping of the uranium groundwater plume.
• ~10 metric tons of U lost to soil at tank BX-102 in 1951
• ~1.5 metric tons of U discharged to Cribs and Trenches
7
Development of the Uranium Groundwater Plume in the B-BX-BY Area
8
Characterization Results for the B-BX-BY WMA and Surrounding Waste Sites Fails to Explain the
Presence of Uranium in Groundwater
• Anthropogenic uranium in the vadose zone was not detected within 190 feet of groundwater at the liquid waste sites
– BY Cribs (DOE/RL-92-70, DOE/RL-2002-42, DOE/GJO-2003-458-TAC)
– 216-B-7A & 7B Cribs (DOE/GJO-2002-343-TAR and DOE/RL-2002-42)
– 216-B-8 Crib (DOE/GJO-2002-343-TAR)
• Modeling results for the waste sites suggest that uranium will not reach groundwater for hundreds of years (DOE/RL-2002-42)
• Characterization of the B-BX-BY WMA (RPP-10098) suggested that the source of uranium in groundwater was from the nearby liquid waste sites
9
Visualization of 238U Vadose ZoneData in the B-BX-BY WMA Area
(Figure from DOE/GJO-2003-545-TAC, which has never been issued)
10
Borehole 299-E33-41 Comparisonof Geophysical Logging Runs
(Figure from CTUIR-DOSE)
• Logged in 1991, 1997, 2002 and 2006
• Significant influx of uranium contamination between log depths of 120 and 247 ft
• Influx occurred between 1991 and 1997
• 2006 results have not been released
• Reference: DOE/GJO-2002-343-TAR)
11
Uranium concentrations tripled between 1997 and 2006 at 299-E33-18
(Figure from Rick McCain, The S.M. Stoller Corp.)
• Logged in 1992, 1997, 2002 and 2006
• Uranium not detected in 1992
• Influx of uranium occurred between 1992 and 1997
• Uranium detected in 1997 and 2006 at log depths between 232 and 264 ft
12
Uranium Vadose Zone Plume Map for the BX-102 Tank Leak (from CTUIR-DOSE)
13
Uranium Vadose Zone Plume Map for the BX Tank Farm (modified from RPP-10098)
14
Visualization of Uranium Vadose Zone Plume for the BX-102 Tank Leak
(Figure from DOE/GJO-2002-343-TAC)
15
16
B-BX-BY FIR underestimates extent of uranium contamination
17
Uranium Concentrations in Groundwater Samples From Wells in Vicinity of B-BX-BY Waste
Management Area (PNNL 11826)
18
Uranium Vadose Zone and Groundwater Contamination from the BX-102 Tank Leak
(Figure from DOE/GJO-2003-545-TAC, which has never been issued)
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BX-102 Tank Leak• The 1951 uranium spill at tank BX-102 is the only
identified source of uranium in groundwater based on geophysical logging results of 287 boreholes ( ~70,000 individual measurements)
• Based on log data, uranium concentrations in the deep vadose zone increased in boreholes 299-E33-41 and 299-E33-18 between 1991 and 2006
• A southeastnorthwest-trending uranium plume has developed in the groundwater since 1993
• DOE’s failure to identify the source of uranium in groundwater casts doubt upon the characterization/remediation efforts at Hanford and the validity of risk modeling
• No short terms goals for RCRA Corrective Action
20
C Tank FarmSpecific Conductance
FY YearAverage
Background (uS/cm)
Critical Mean
(uS/cm)Reference
2005 584.6 943 PNNL-15670
2002 Not Reported ~530 PNNL-14187
2000 349.8 553.5 PNNL-13404
1998 353.1 543.9 PNNL-12086
1996 353.1 543.9 PNNL-11470
21
22
Cobalt-60 in deep vadose zone at C tank Farm
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Ongoing Migration of Co-60 Since 1978 at 30-08-02 (near Tank C-108)
(Figure from DOE/GJO–2003–400–TAC)
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C Tank Farm
• C Tank Farm is the source of the recent Tc-99 groundwater plume
• Groundwater monitoring network lacks upgradient well
• Co-60 detected in vadose zone outside of the fence line
• Ongoing migration of radionuclides in the vadose zone
• Insufficient characterization for closure
25
IssuesTank Leak Volume Estimates
(RPP-23405, Rev. 1)• Inconsistent tank leak criteria• Reduction of documented leaks without a
technical basis• Multiple leaks from a tank• Highest gamma activity results not considered• Minimum leak detection volume• Tank leaks attributed to surface spills• Misuse of krigging estimates• Dismissal of the Historical Leak Model (HNF-
3233)
26
Inconsistent tank leak criteria
• Evidence of a tank leak (RPP-23405)– Cs-137 activities greater than 10,000 pCi/g– Below base of tank
• Inconsistent with field results– Maximum Cs-137detected with SGLS near
bases of SX-115 and SX-113 are less than 10 pCi/g
• 50,000 gallons lost at SX-115• More than 15,000 gallons lost at SX-113
27
Evidence of tank leaks not always considered in RPP-23405
• Radionuclides other than Cs-137– Co-60, Eu-152, Eu-154, Nb-94, Sb-125, Sn-
126, U-235, and U-238
• Lower levels of Cs-137 (i.e. TY-102)
• Logging anomalies on gross gamma data
28
Reduction of documented leak volumes without a technical basis
• RPP-23405 estimates 1,000 gallon leak SX-112– ARH-R-43 is not discussed or referenced in the
section on SX-112 in RPP-23405– ARH-R-43 is listed as reference in RPP-23405
• ARH-R-43 reported a leak of 30,000 gallons from SX-112 based on:– Liquid level measurements– Soil radiation readings
29
Multiple leaks from a tank
• Represented as single event– Volume from one leak event represented in RPP-23405
• Examples– A-105
• Reported as a 1,000 gallon leak in RPP-23405• Unstable liner resulted in 26 “suck back occurrences” (ARH-78) not
discussed in RPP-23405• Gross gamma logging results for the laterals (RPP-26705)
– Maximum estimated Cs-137 encountered was 34 million pCi/g
– SX-113• Volume “well documented” according to RPP-23405• 1958 leak event (HW-56972)• 1962 leak test• Only the 15,000 gallon leak from the leak test is reported in RPP-23405
30
Highest Gamma ActivityResults Not Considered
• Activities greater than 10,000 pCi/g below base of tank criteria for a tank leak according to RPP-23405
• Examples where RPP-23405 should have developed leak estimates– B-105 (20-05-06 and 20-06-06) – TX-114 (51-14-04)– BX-110 (21-10-05)
31
Cs-137 Described as “Isolated Narrow Band” in RPP-23405, Rev. 1
32
Tank BX-110Description of 21-10-05
33
Minimum Leak Detection Volume
• Assumed as 1,000 gallons in RPP-23405• De-Minimus leak volume estimate (Appendix A, RPP-23405)
– 5,000 gallons– Issues
• Differences in stratigraphy underneath the tanks• Number of drywells• Depth of drywells• Location of tank leak• Based on moisture measurements instead of gamma activity which was
actually measured• In-tank levels reported to nearest inch for many years
– Waste transfers reported to nearest 1,000 gallons (HW-83906)– One inch change in a 75 ft diameter tank is ~2750 gallons (HW-83906)
• Maximum permissible leak was 50,000 gallons (HW-68661)
34
Misuse of Krigging Estimates
• BY Tank Farm• SX Tank Farm
– IPEP’s review of krigging estimate (HNF-5782) is ignored
– Gross gamma logging results for the laterals (RPP-26705)
• Maximum estimated Cs-137 encountered was greater than 200 million pCi/g
• Upper limit for Cs-137 detected by HRLS in drywells had appeared to be 100 million pCi/g
– Krigging based on data from HNF-5782 underestimates leak volumes in SX tank farm
• Upper limit for Cs-137 appeared to be ~50 million pCi/g (under SX-107)
35
Tank Leaks Attributed to Surface Spills
• BY Tank Farm– RPP-23405 claims Co-
60 detected below base of tanks is from the surface
– This claim is not supported by SGLS data (i.e. 22-12-03)
• Co-60 detected between 3 and 15 ft bgs is unrelated to Co-60 detected below 83 ft bgs
36
Historical Leak Model (HNF-3233)
• Premature dismissal by HNF-4756• Recent logging results (RPP-26705) may
validate estimates in HNF-3233– Maximum Cs-137 in laterals under SX-108 was
estimated (HNF-5782) at between 5 and 50 million pCi/g versus 200 million pCi/g (RPP-26705)
– RPP-6285 estimates based on krigging may be an order of magnitude low for SX-108
• Field data tend to support HNF-3233 tank leak estimates
37
Conclusions
• Tank Farms are the source of recent groundwater plumes in 200 East, absence of RCRA Corrective Action
• DOE’s failure to identify the source of uranium in 200 East groundwater casts doubt upon the characterization/remediation efforts at Hanford and the validity of risk modeling
• Soil samples have not been acquired in any of the areas with ongoing migration of radionuclides
• RPP-23405 provides questionable estimates of past tank leaks. Unsupported estimates from RPP-23405 should not be used in any risk modeling
• Historical Leak Model (HNF-3233) estimates should be used as an upper limit for SX tank leaks