ute Cee et le i 7” Magn =P - ast es ==. wee. . ee os ‘ 29 of the dome, may be near “equilibrium” since it is close to ti extension of the near subsurface beachrock (Byron Ristvet, let the committee, November 1981). The coamittee believes that the probability of dome brea to storm wave and typhoon activity is quite low. However, to tate early detection of typiocn-tnduced effects it recommends visual inspection of the dome structure, the surrounding mole, beach on the lagoon side be performed at regular intervals (as minimum, after each major typhoon). Some settling with time in response to loading is concei Furthermore, vegetation such as tree limbs included within the can be expected to undergo bacteriological reduction, result Slight amounts of settlement within the dome. access to the contained dome cap in response to vided by the key-wall. slightly in response to cap functions simply as Such settlement,} how- material. Resistance against movement Bf the settlement of the contents of the dome Although the key-wall may spread outwar stresses produced by settlement, the a series of cover slabs, not a true com tial settlement or settle without any impairment of the dome's formance. that the tremie and the soil-cement operations were not fully cessful. Within the tremie region there are zones of oversized[debris and unconsolidated tremie material that provide channels for wa movement. The rapid tidal response in the boreholes indicates water in the structure is closely coupled to the island's gro Therefore, at least part of the radioactivity contained in the ture is available for transport to the groundwater and, subsequ to the lagoon, and it is important to determine whether this pa may be a significant one. It is not clear whether Cactus Crater (and its vicinity) is greater or lesser source of transuranic movement to the lagoon was before the cleanup. Before Cactus Crater was filled it was the gources cf transuranics being remobilized to the waters of lagoon. Noshkin estimates that about 0.4 percent of the dissoiv plutonium present in the lagoon originated from the material at bottom of the crater (V.E. Noshkin, personal communication to 2. Morse, October 23, 1981). Several conditions, however, were cha by the cleanup operations: the fresh water run-off to the water was changed by the construction of the dome; the cleanup of soil island has reduced movement of transurznics to the groundwater; filling of the crater has modified the amount of transuranics be transported from the crater. It is possible to demonstrate that leaching from the dome create a significant new hazard by use of simple inventory arg without having to speculate aL.out possible remobilization proces taking place within the structure. It was indicated in sectior tha* there is about 1.5 Ci of plutonium continuously in solution lag > and that 3.0 Ci are lost to th ocean annually. The amou :