Common use of Repository Clause in Contracts

Repository. Monthly, quarterly, and annual inspections of the repository ensure that remedy controls remain intact and that the waste remains isolated from the environment. Inspection observations and maintenance activities for the quarter are as follows: • No area of the cover indicated settling, slumping, fracturing, seepage, ponding, or significant erosion. • No anomalous surface feature conditions were observed at the disposal cell or Pond 4. Surveillance checklists for this quarter are attached as Appendix A. • The minor burrowing on the disposal cell and the Pond 4 berm by voles and small ground squirrels was not observed this quarter due to the depth of snow that covers both the disposal cell and Pond 4 berms. Previously observed xxxxxxx were not deep and did not pose a concern. • The disposal cell LCRS and LDS were operated in accordance with the requirements specified in the LTS&M Plan. Findings for the disposal cell LCRS and LDS this period include: ⎯ Leachate production from the disposal cell was approximately 600 gallons per week combined for LCRS sumps LCRS 1 and LCRS 2. There is no action level for the disposal cell LCRS. See Appendix B for a graphical depiction of leachate production history. ⎯ The disposal cell LDS continues to receive no water; therefore, the disposal cell LDS action level was not exceeded. See Appendix B for a graphical depiction of leachate production history. • Operation of the GRO system has resulted in increased water collection in the Pond 4 LCRS and LDS. However, the Pond 4 LCRS and LDS monitoring and pumping systems continue to function as designed, to circulate water back to the pond. Findings for the Pond 4 LCRS and LDS this period include: ⎯ Water collection at the Pond 4 LCRS continued to exceed the action level between January and March (see Appendix B). LM has previously notified EPA and UDEQ of this Pond 4 action level exceedance. ⎯ Water collection in the Pond 4 LDS remained below the action level (see Appendix B). LM has previously notified EPA and UDEQ of water collection and removal in the Pond 4 LDS. U.S. Department of Energy Monticello NPL Sites FFA Quarterly Report: January 1–March 31, 2019 May 2019 Doc. No. S25044

Repository. Monthly, quarterly, and annual inspections of the repository ensure that remedy controls remain intact and that the waste remains isolated from the environment. Inspection observations and maintenance activities for the quarter are as followsreporting period are: • No area of the cover indicated settling, slumping, fracturing, seepage, ponding, or significant erosion. • No anomalous surface feature conditions were observed at the disposal cell or Pond 4. Surveillance repository with respect to the surveillance items included in the LTS&M repository area surveillance checklists (attached for this quarter in Appendix A). • Water accumulation in Pond 4 has increased with the start-up of the OU III groundwater contingency remedy optimization system. Approximately 4 feet of water was in the pond at the time of the March monthly pond inspection. Monthly Pond 4 surveillance checklists are attached as Appendix A. • The minor burrowing on the disposal cell and the Pond 4 berm by voles and small ground squirrels was not observed for this quarter due to the depth of snow that covers both the disposal cell and Pond 4 berms. Previously observed xxxxxxx were not deep and did not pose a concern. in Appendix A.‌‌ • The disposal cell LCRS and LDS were operated in accordance with the requirements specified in the LTS&M Plan. Findings for the disposal cell LCRS and LDS this period include: ⎯ Leachate production from the disposal cell repository was approximately 600 normal. Leachate production is about 1,000 gallons per week combined for LCRS sumps LCRS 1 and LCRS 2. There is no action level for the disposal cell LCRS. See Appendix B for a graphical depiction of leachate production history. ⎯ The disposal cell LDS continues to receive no water; therefore, the disposal cell LDS action level was not exceeded. See Appendix B for a graphical depiction of leachate production history. • Operation Inspection and repairs were performed of the GRO primary Pond 4 liner in 2013 and 2014. However, operation of the OU III groundwater contingency remedy optimization system has resulted in increased water collection in the Pond 4 LCRS. The LCRS recirculation system is operating as intended and LDSthe action level leakage rate, as described in Section 3.4 of the LTS&M Plan, has not been exceeded. However, the Pond 4 LCRS and LDS monitoring and pumping systems continue to function performance history is summarized as designed, to circulate water back to the pond. Findings a graph in Appendix B. • The lower sumps (LDS) for the repository and Pond 4 LCRS received no water during the quarter. This is the normal condition. Graphs showing the performance history for the repository LDS and LDS this period include: ⎯ Water collection at the Pond 4 LCRS continued to exceed the action level between January and March (see Appendix B). LM has previously notified EPA and UDEQ of this Pond 4 action level exceedance. ⎯ Water collection in the Pond 4 LDS remained below the action level (see are included in Appendix B). LM has previously notified EPA and UDEQ B. • Approximately 190 gallons of water collection and removal was pumped from the repository LDS 2 sump in January 2015 during routine pump control maintenance activities. The water removed is considered remnant from past testing activities, rather than liner leakage. Historic water levels in the Pond 4 LDS. U.S. Department of Energy Monticello NPL Sites FFA Quarterly Report: January 1–March 31, 2019 May 2019 Doc. No. S25044sump have remained essentially static.

Repository. Monthly, quarterly, and annual inspections of the repository ensure that remedy controls remain intact and that the waste remains isolated from the environment. Inspection observations and maintenance activities for the quarter are as follows: • No area of the cover indicated settling, slumping, fracturing, seepage, ponding, or significant erosion. • No anomalous surface feature conditions were observed at the disposal cell or and Pond 4. Surveillance checklists for this quarter are attached as Appendix A. • The minor Minor burrowing on the disposal cell and the Pond 4 berm by voles and small ground squirrels was not observed this quarter due continue to the depth of snow that covers both the disposal cell and Pond 4 bermsbe observed. Previously observed These xxxxxxx were are not deep and did do not pose a concern. • The disposal cell LCRS and LDS were operated in accordance with the requirements specified in the LTS&M Plan. Findings for the disposal cell LCRS and LDS this period include: ⎯ Leachate production from the disposal cell was approximately 600 1150 gallons per week combined for LCRS sumps LCRS 1 and LCRS 2. There is no action level for the disposal cell LCRS. See Appendix B for a graphical depiction of leachate production history. ⎯ The disposal cell LDS continues to receive no water; therefore, the disposal cell LDS action level was not exceeded. See Appendix B for a graphical depiction of leachate production history. U.S. Department of Energy Monticello NPL Sites FFA Quarterly Report: July–September 2018 November 2018 Doc. No. S22073 • Operation of the GRO system has resulted in increased water collection in the Pond 4 LCRS and LDS. However, the The Pond 4 LCRS and LDS monitoring and pumping systems continue to function are functioning as designed, intended to circulate water back to the pond. Findings for the Pond 4 LCRS and LDS this period include: pond.‌‌ ⎯ Water collection at the Pond 4 LCRS continued to exceed exceeded the action level between January July and March August but was below the action level in September (see Appendix B). LM has previously notified EPA and UDEQ of this Pond 4 action level exceedance. ⎯ Water collection in the Pond 4 LDS remained below the action level (see Appendix B). LM has previously notified EPA and UDEQ of water collection and removal in the Pond 4 LDS. U.S. Department of Energy Monticello NPL Sites FFA Quarterly Report: January 1–March 31, 2019 May 2019 Doc. No. S25044.

Repository. Monthly, quarterly, and annual inspections of the repository ensure that remedy controls remain intact and that the waste remains isolated from the environment. Inspection observations and maintenance activities for the quarter are as follows: • No area of the cover indicated settling, slumping, fracturing, seepage, ponding, or significant erosion. • No anomalous surface feature conditions were observed at the disposal cell or and Pond 4. Surveillance checklists for this quarter are attached as Appendix A. • The minor Minor burrowing on the disposal cell and the Pond 4 berm by voles and small ground squirrels was not observed this quarter due continue to the depth of snow that covers both the disposal cell and Pond 4 bermsbe observed. Previously observed These xxxxxxx were are not deep and did do not pose a concern. • The disposal cell LCRS and LDS were operated in accordance with the requirements specified in the LTS&M Plan. Findings for the disposal cell LCRS and LDS this period include: ⎯  Leachate production from the disposal cell was approximately 600 1150 gallons per week combined for LCRS sumps LCRS 1 and LCRS 2. There is no action level for the disposal cell LCRS. See Appendix B for a graphical depiction of leachate production history. ⎯  The disposal cell LDS continues to receive no water; therefore, the disposal cell LDS action level was not exceeded. See Appendix B for a graphical depiction of leachate production history. U.S. Department of Energy Monticello NPL Sites FFA Quarterly Report: July–September 2018 November 2018 Doc. No. S22073 • Operation of the GRO system has resulted in increased water collection in the Pond 4 LCRS and LDS. However, the The Pond 4 LCRS and LDS monitoring and pumping systems continue to function are functioning as designed, intended to circulate water back to the pond. Findings for the Pond 4 LCRS and LDS this period include: ⎯ pond.‌‌  Water collection at the Pond 4 LCRS continued to exceed exceeded the action level between January July and March August but was below the action level in September (see Appendix B). LM has previously notified EPA and UDEQ of this Pond 4 action level exceedance. ⎯  Water collection in the Pond 4 LDS remained below the action level (see Appendix B). LM has previously notified EPA and UDEQ of water collection and removal in the Pond 4 LDS. U.S. Department of Energy Monticello NPL Sites FFA Quarterly Report: January 1–March 31, 2019 May 2019 Doc. No. S25044.

Repository. Monthly, quarterly, and annual inspections of the repository ensure that remedy controls remain intact and that the waste remains isolated from the environment. Inspection observations and maintenance activities for the quarter are as follows: • No area of the cover indicated settling, slumping, fracturing, seepage, ponding, or significant erosion. • No anomalous surface feature conditions were observed at the disposal cell or Pond 4. Surveillance checklists for this quarter are attached as Appendix A. • The minor burrowing on the disposal cell and the Pond 4 berm by voles and small ground squirrels was not observed this quarter due to the depth of snow that covers both the disposal cell and Pond 4 berms. Previously observed xxxxxxx were not deep and did not pose a concern. • The disposal cell LCRS and LDS were operated in accordance with the requirements specified in the LTS&M Plan. Findings for the disposal cell LCRS and LDS this period include: ⎯  Leachate production from the disposal cell was approximately 600 gallons per week combined for LCRS sumps LCRS 1 and LCRS 2. There is no action level for the disposal cell LCRS. See Appendix B for a graphical depiction of leachate production history. ⎯  The disposal cell LDS continues to receive no water; therefore, the disposal cell LDS action level was not exceeded. See Appendix B for a graphical depiction of leachate production history. • Operation of the GRO system has resulted in increased water collection in the Pond 4 LCRS and LDS. However, the Pond 4 LCRS and LDS monitoring and pumping systems continue to function as designed, to circulate water back to the pond. Findings for the Pond 4 LCRS and LDS this period include: ⎯  Water collection at the Pond 4 LCRS continued to exceed the action level between January and March (see Appendix B). LM has previously notified EPA and UDEQ of this Pond 4 action level exceedance. ⎯  Water collection in the Pond 4 LDS remained below the action level (see Appendix B). LM has previously notified EPA and UDEQ of water collection and removal in the Pond 4 LDS. U.S. Department of Energy Monticello NPL Sites FFA Quarterly Report: January 1–March 31, 2019 May 2019 Doc. No. S25044