1 Issues for the Tank Waste Committee Hanford Advisorary Board October 10, 2006.

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Issues for the Tank Waste CommitteeHanford Advisorary Board

October 10, 2006

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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)

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Tank Farms located in 200 East(Figure from DOE/ORP-2005-1)

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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

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Handbook of Groundwater Protection and Cleanup Policies for RCRA Corrective Action

EPA530-R-04-030

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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

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Development of the Uranium Groundwater Plume in the B-BX-BY Area

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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

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Visualization of 238U Vadose ZoneData in the B-BX-BY WMA Area

(Figure from DOE/GJO-2003-545-TAC, which has never been issued)

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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)

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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

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Uranium Vadose Zone Plume Map for the BX-102 Tank Leak (from CTUIR-DOSE)

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Uranium Vadose Zone Plume Map for the BX Tank Farm (modified from RPP-10098)

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Visualization of Uranium Vadose Zone Plume for the BX-102 Tank Leak

(Figure from DOE/GJO-2002-343-TAC)

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B-BX-BY FIR underestimates extent of uranium contamination

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Uranium Concentrations in Groundwater Samples From Wells in Vicinity of B-BX-BY Waste

Management Area (PNNL 11826)

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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

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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

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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

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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)

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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

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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

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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

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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

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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)

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

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Tank BX-110Description of 21-10-05

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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)

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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)

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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

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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

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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