1 Issues for the Tank Waste Committee Hanford 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 )

3 Tank Farms located in 200 East (Figure from DOE/ORP )

4 Ongoing degradation of groundwater due to past tank leaks

5 Handbook of Groundwater Protection and Cleanup Policies for RCRA Corrective Action EPA530-R

6 PNNL Annual Groundwater Monitoring B-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 , DOE/GJO TAC) –216-B-7A & 7B Cribs (DOE/GJO TAR and DOE/RL ) –216-B-8 Crib (DOE/GJO TAR) Modeling results for the waste sites suggest that uranium will not reach groundwater for hundreds of years (DOE/RL ) 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 238 U Vadose Zone Data in the B-BX-BY WMA Area (Figure from DOE/GJO TAC, which has never been issued)

10 Borehole 299-E33-41 Comparison of 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 results have not been released Reference: DOE/GJO 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 TAC)

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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 TAC, which has never been issued)

19 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 southeast  northwest-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 Farm Specific Conductance FY Year Average Background (uS/cm) Critical Mean (uS/cm) Reference PNNL Not Reported~530PNNL PNNL PNNL PNNL-11470

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22 Cobalt-60 in deep vadose zone at C tank Farm

23 Ongoing Migration of Co-60 Since 1978 at (near Tank C-108) (Figure from DOE/GJO–2003–400–TAC)

24 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 Issues Tank 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 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 estimates 1,000 gallon leak SX-112 –ARH-R-43 is not discussed or referenced in the section on SX-112 in RPP –ARH-R-43 is listed as reference in RPP 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 Examples –A-105 Reported as a 1,000 gallon leak in RPP Unstable liner resulted in 26 “suck back occurrences” (ARH-78) not discussed in RPP 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 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 Activity Results Not Considered Activities greater than 10,000 pCi/g below base of tank criteria for a tank leak according to RPP Examples where RPP should have developed leak estimates –B-105 ( and ) –TX-114 ( ) –BX-110 ( )

31 Cs-137 Described as “Isolated Narrow Band” in RPP-23405, Rev. 1

32 Tank BX-110 Description of

33 Minimum Leak Detection Volume Assumed as 1,000 gallons in RPP 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 ) 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 claims Co- 60 detected below base of tanks is from the surface –This claim is not supported by SGLS data (i.e ) 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 provides questionable estimates of past tank leaks. Unsupported estimates from RPP 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