Review of Waste Retrieval Sluicing System Operations and Data for Tanks 241-C-106 and 241-AY-102

Abstract

Sluicing operations were performed to retrieve high-heat sludge from single-shell tank (SST) 241-C-106 (C-106) and transfw it to double-shell tank 241-AY-102 (AY-102) using the Waste Retrieval Sluicing System. This has eliminated the high-heat safety issue for C-106 and demonstrates a technology for retrieval of SST waste. The behaviors of AY-102 and C-106 were monitored during the waste transfer operations, providing a clear picture of general trends in each tank. Specific issues addressed were evaluation of the data for evidence of flammable gas accumulation in AY-102 and thermal performance of AY-102 under the increasing heat load. Reports summarizing the data were produced on a regular basis from September 1998 through October 1999 and posted to a web page on the internal Hanford intranet. This greatly facilitated communication between the contractors, Pacif3c Northwest National Laboratory and the Office of River Protection during the operations. Sluicing operations were canied out in a series of three campaigns, each of which removed approximately one-third of the C-106 sludge. The first campaign was initiated on November 10, 1998, with the fti transfer of sludge from C-106 to AY-102, and was concluded on March 28, 1999. Unexpected delays were encountered due to unacceptably large releases of volatile organic compounds (VOCS) through the C-006 ventilation stack when operations fmt disturbed the deep layers of sludge in C-106. (Release mtes were measured in excess of 450 ppm when the permitted limit was 50 ppm.) Changes @procedures and equipment mitigated this problem, and in the following campaigns, the VOC release rate never exceeded the permitted limit. The initial estimate based on sluicing data indicated that 75,405 gallons of sludge (approximately 40% of the 192,000 gal originally in C-106) were transferred to AY-102 in Campaign #1. Campaign #2 was initiated on April 23, 1999 after meeting the requirements of hydrogen release rate and level change to determine that gas was not being retained h"the waste that had been transferred to AY-102. The amount transferred in Campaign #2, which was terminated on June 3, 1999, was initially estimated as 51,482 gal of sludge. This represents about 27°/0 of the initial sludge volume in C-106, resulting in an estimated 66% transferred to AY-102 in the frst two campaigns. Campaign #3 was initiated on July 21, 1999 and continued in 12 separate batches until October 6, 1999. The amount transferred in this campaign was initially estimated as 59,000 gal of sludge, or about 31YOof the original amount in C-106. A total transfer amount of approximately 186,000 gal, or 97Y0,was estimated from measurements during sluicing. Estimates obtained from thermal analyses of C-106 and AY-102 and other independent calculation methods post-sluicing indicate that at least 182,000 gallons, or 95°/0 and up to 188,000 gallons, or 98?40,of the original C-106 sludge was transferred to AY-102. The video inspection pefiormed in C-106 in July 2000 clearly shows that about 45,000 gal of waste remai...

Effects of Globally Waste Disturbing Activities on Gas Generation, Retention, and Release in Hanford Waste Tanks

“…Each sluicing batch removed several inches to a foot of sludge and resulted in an increase in headspace hydrogen concentration from a baseline of 20-30 ppm to 400-500 ppm. Hydrogen was also liberated in the receiver tank, AY-102, usually increasing to about 100 ppm during sluicing (Cuta et al 2000).…”

Simulant Basis for the Standard High Solids Vessel Design

“…The in situ settling rates provide actual waste process performance data against which the developed mineral phase density and size distributions can be compared. The AZ-101 interface settling rate data are from the WFD mixer pump operation tests (as described in Carlson et al 2001), and the AY-102 data are from the sluicing retrieval of C-106 into AY-102 (Cuta et al 2000). The AZ-101 data represent a much more direct interface settling rate measurement than the AY-102 data; see Wells et al 2011 compared the in situ settling rate process performance data to particle settling rate data for that waste to establish the basis for waste characterization.…”

Effects of Globally Waste-Disturbing Activities on Gas Generation, Retention, and Release in Hanford Waste Tanks

“…As much as 300 scf/day of gas was released during sluicing. Hydrogen was also liberated in the receiver tank, AY-102, usually increasing to about 100 ppm during sluicing (Cuta et al 2000).…”