Ferrocyanide Safety Program rationale for removing six tanks from the safety watch list

Abstract

This report compiles informationfrom a varietyof sources to provide a technicalbasis for removing tanks241-BX-102,-106,-110,-111,241-BY-101, and 241-T-101 from the FerrocyanideWatch List. Includedare detailed descriptions of waste transferoperations, and waste transferdata for the period tankswere in service. Also included is information consideredby the Departmentof Energy for authorization to stabilize tank24 IT -101. Some of the tanksreceived "sidepocketed"supematantbecause of high 6°Coor 9°Sr concentration. The soluble ferrocyanidecontent of the settled supematantwas very low, and it is importantto note that ferrocyanideion was not added in excess of nickel ion during scavenging. A thorough review of the availableferrocyanidescavenging records concluded that tank 241-T-101 (because it was refilled with metal waste and sluiced again in 1956 after receiving ferrocyanide sludge in 1953); tanks241-BX-102,-106, and 241-BY-101 (because these tanks received only ferrocyanidescavenging supematant);and tanks241-BX-110 and-111 (because these tanksdid not receive any ferrocyanidewaste, sludge or supematant)do not containthe requisite 1000 g-moles or more of ferrocyanide. Therefore, these six tanks do not belong on the FerrocyanideWatch List.

Tank characterization report for single-shell tank 241-BY-106

“…The mean nickel concentration based on segment 13 of core 65 was 29,500 &g. If all the nickel originated from Na,NiFe(CN),, then the observed nickel concentration indicates that 159,000 pg/g of Na,NiFe(CN), [89,870 kg of Na,NiFe(CN), based on the HTCE density value of 1.58 g/mL and sludge volume from Hanlon (1996)l existed in the tank before degradation. This number is vastly different from the ones from the HTCE and Borsheim and Simpson (1991). It suggests that the sludge sample obtained may not be representative of the ferrocyanide sludge, at least with respect to nickel.…”

“…According to Borsheim and Simpson (1991), 14,000 kg of Na,NiFe(CN), was expected to remain in the tank at the end of the ferrocyanide waste transfer activity in 1957. This number is reasonably close to the Na,NiFe(CN), inventory of 12,800 kg calculated based on the HTCE concentration for Fe(CN);-of 0.0167 M, the HTCE density value of 1.58 g/mL, and the HTCE total mass for the waste of 3.84E+06 kg.…”

“…Estimation of the amount of degradation of N+NiFe(CN), based on the current concentration of cyanide uses the range of values from Borsheim and Simpson (1991) and the HTCE (12,800 kg-14,000 kg). The recent total cyanide analytical mean from segment 13 of core 65 is 93.9 pg/g (57.8 kg of cyanide) which is equivalent to 117 kg of Na,NiFe(CN),.…”

Quarterly report on the Ferrocyanide Safety Program for the period ending September 30, 1995

“…In October 1990 (Deaton 1990), the Ferrocyanide Safety Issue was declared a USQ (see Section 2.1) because the safety envelope for these tanlcs was no longer considered to be bounded by the existing safety analysis report (Smith 1986 (Harmon 1991), the 24 ferrocyanide tanks were among the tanks identified, and were included in the subsequent July 1991 report to Congress (Watkins 1991) that responded to the Wyden Amendment. However, re-examination of the historical records (Borsheim and Simpson 1991) indicated that six of the 24 tanks did not contain the requisite 1,OOO g-moles of ferrocyanide. Therefore, these six tanks should not have been included on the Watch List nor identified in the response to the Wyden Amendment.…”

Quarterly report on the Ferrocyanide Safety Program for the period ending June 30, 1994

“…In February 1991 (Harmon 1991), the 24 ferrocyanide tanks were among the tanks identified, and were included in the subsequent July 1991 report to Congress (Watkins 1991) that responded to the Wyden Amendment. However, re-examination of the historical records (Borsheim and Simpson 1991) indicated that six of the 24 tanks did not contain the requisite 1, OOO g-moles of ferrocyanide. Therefore, these six tanks should not have been included on the Watch List nor been identified in the response to the Wyden Amendment.…”