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Title: Mechanistic analysis of double-shell tank gas release

Abstract

Pacific Northwest Laboratory (PNL) is studying possible mechanisms and fluid dynamics contributing to the periodic release of gases from the double-shell waste storage tanks at Hanford. This study is being conducted for Westinghouse Hanford Company (WHC), a contractor for the US Department of Energy (DOE). This interim report discusses the work done through November 1990. Safe management of the wastes at Hanford depends on an understanding of the chemical and physical mechanisms that take place in the waste tanks. An example of the need to understand these mechanisms is tank 101-SY. The waste in this tank is generating and periodically releasing potentially flammable gases into the tank vent system according to observations of the tank. How these gases are generated and become trapped, the causes of periodic release, and the mechanism of the release are not known in detail. In order to develop a safe mitigation strategy, possible physical mechanisms for the periodic release of flammable gases need to be understood.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest Lab., Richland, WA (United States)
Sponsoring Org.:
USDOE; USDOE, Washington, DC (United States)
OSTI Identifier:
5671477
Report Number(s):
PNL-7657
ON: DE92009029
DOE Contract Number:
AC06-76RL01830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 42 ENGINEERING; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; HANFORD RESERVATION; TANKS; LIQUID WASTES; CHEMICAL COMPOSITION; PHYSICAL PROPERTIES; RADIOACTIVE WASTES; BUBBLES; CHEMICAL ANALYSIS; DATA ACQUISITION; FLAMMABILITY; FLOW RATE; FLUID FLOW; HEAT TRANSFER; HYDROGEN; HYDROSTATICS; MATHEMATICAL MODELS; MITIGATION; NATURAL CONVECTION; PRESSURE EFFECTS; PROGRESS REPORT; QUANTITY RATIO; RHEOLOGY; SAMPLING; SLURRIES; STRESSES; THERMAL CONDUCTIVITY; VOLUME; COMBUSTION PROPERTIES; CONTAINERS; CONVECTION; DISPERSIONS; DOCUMENT TYPES; ELEMENTS; ENERGY TRANSFER; MASS TRANSFER; MATERIALS; MIXTURES; NATIONAL ORGANIZATIONS; NONMETALS; RADIOACTIVE MATERIALS; SUSPENSIONS; THERMODYNAMIC PROPERTIES; US DOE; US ERDA; US ORGANIZATIONS; WASTES; 052002* - Nuclear Fuels- Waste Disposal & Storage; 420400 - Engineering- Heat Transfer & Fluid Flow; 400800 - Combustion, Pyrolysis, & High-Temperature Chemistry

Citation Formats

Allemann, R.T., Antoniak, Z.I., Friley, J.R., Haines, C.E., Liljegren, L.M., and Somasundaram, S. Mechanistic analysis of double-shell tank gas release. United States: N. p., 1991. Web. doi:10.2172/5671477.
Allemann, R.T., Antoniak, Z.I., Friley, J.R., Haines, C.E., Liljegren, L.M., & Somasundaram, S. Mechanistic analysis of double-shell tank gas release. United States. doi:10.2172/5671477.
Allemann, R.T., Antoniak, Z.I., Friley, J.R., Haines, C.E., Liljegren, L.M., and Somasundaram, S. 1991. "Mechanistic analysis of double-shell tank gas release". United States. doi:10.2172/5671477. https://www.osti.gov/servlets/purl/5671477.
@article{osti_5671477,
title = {Mechanistic analysis of double-shell tank gas release},
author = {Allemann, R.T. and Antoniak, Z.I. and Friley, J.R. and Haines, C.E. and Liljegren, L.M. and Somasundaram, S.},
abstractNote = {Pacific Northwest Laboratory (PNL) is studying possible mechanisms and fluid dynamics contributing to the periodic release of gases from the double-shell waste storage tanks at Hanford. This study is being conducted for Westinghouse Hanford Company (WHC), a contractor for the US Department of Energy (DOE). This interim report discusses the work done through November 1990. Safe management of the wastes at Hanford depends on an understanding of the chemical and physical mechanisms that take place in the waste tanks. An example of the need to understand these mechanisms is tank 101-SY. The waste in this tank is generating and periodically releasing potentially flammable gases into the tank vent system according to observations of the tank. How these gases are generated and become trapped, the causes of periodic release, and the mechanism of the release are not known in detail. In order to develop a safe mitigation strategy, possible physical mechanisms for the periodic release of flammable gases need to be understood.},
doi = {10.2172/5671477},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1991,
month =
}

Technical Report:

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  • Pacific Northwest Laboratory (PNL) is studying possible mechanisms and fluid dynamics contributing to the periodic release of gases from the double-shell waste storage tanks at Hanford. This study is being conducted for Westinghouse Hanford Company (WHC), a contractor for the US Department of Energy (DOE). This interim report discusses the work done through November 1990. Safe management of the wastes at Hanford depends on an understanding of the chemical and physical mechanisms that take place in the waste tanks. An example of the need to understand these mechanisms is tank 101-SY. The waste in this tank is generating and periodicallymore » releasing potentially flammable gases into the tank vent system according to observations of the tank. How these gases are generated and become trapped, the causes of periodic release, and the mechanism of the release are not known in detail. In order to develop a safe mitigation strategy, possible physical mechanisms for the periodic release of flammable gases need to be understood.« less
  • M&D Professional Services, Inc. (M&D) is under subcontract to Pacific Northwest National Laboratories (PNNL) to perform seismic analysis of the Hanford Site Double-Shell Tanks (DSTs) in support of a project entitled ''Double-Shell Tank (DSV Integrity Project-DST Thermal and Seismic Analyses)''. The overall scope of the project is to complete an up-to-date comprehensive analysis of record of the DST System at Hanford in support of Tri-Party Agreement Milestone M-48-14. The work described herein was performed in support of the seismic analysis of the DSTs. The thermal and operating loads analysis of the DSTs is documented in Rinker et al. (2004). Themore » overall seismic analysis of the DSTs is being performed with the general-purpose finite element code ANSYS'. The global model used for the seismic analysis of the DSTs includes the DST structure, the contained waste, and the surrounding soil. The seismic analysis of the DSTs must address the fluid-structure interaction behavior and sloshing response of the primary tank and contained liquid. ANSYS has demonstrated capabilities for structural analysis, but has more limited capabilities for fluid-structure interaction analysis. The purpose of this study is to demonstrate the capabilities and investigate the limitations of the finite element code MSC.Dytranz for performing a dynamic fluid-structure interaction analysis of the primary tank and contained waste. To this end, the Dytran solutions are benchmarked against theoretical solutions appearing in BNL 1995, when such theoretical solutions exist. When theoretical solutions were not available, comparisons were made to theoretical solutions to similar problems, and to the results from ANSYS simulations. Both rigid tank and flexible tank configurations were analyzed with Dytran. The response parameters of interest that are evaluated in this study are the total hydrodynamic reaction forces, the impulsive and convective mode frequencies, the waste pressures, and slosh heights. To a limited extent, primary tank stresses are also reported. The capabilities and limitations of ANSYS for performing a fluid-structure interaction analysis of the primary tank and contained waste were explored in a parallel investigation and documented in a companion report (Carpenter and Abatt [2006]). The results of this study were used in conjunction with the results of the global ANSYS analysis reported in Carpenter et al. (2006) and the parallel ANSYS fluid-structure interaction analysis to help determine if a more refined sub-model of the primary tank is necessary to capture the important fluid-structure interaction effects in the tank and if so, how to best utilize a refined sub-model of the primary tank. The results of this study demonstrate that Dytran has the capability to perform fluid-structure interaction analysis of a primary tank subjected to seismic loading. With the exception of some isolated peak pressures and to a lesser extent peak stresses, the results agreed very well with theoretical solutions. The benchmarking study documented in Carpenter and Abatt (2006) showed that the ANSYS model used in that study captured much of the fluid-structure interaction (FSI) behavior, but did have limitations for predicting the convective response of the waste. While Dytran appears to have stronger capabilities for the analysis of the FSI behavior in the primary tank, it is more practical to use ANSYS for the global evaluation of the tank. Thus, Dytran served the purpose of helping to identify limitations in the ANSYS FSI analysis so that those limitations can be addressed in the structural evaluation of the primary tank.« less
  • This report gives the results of work conducted in FY 1993 by the Tank Waste Processing Analysis Task for the Underground Storage Tank Integrated Demonstration. The main purpose of this task, led by Pacific Northwest Laboratory, is to demonstrate a methodology to identify processing sequences, i.e., the order in which a tank should be processed. In turn, these sequences may be used to assist in the development of time-phased deployment schedules. Time-phased deployment is implementation of pretreatment technologies over a period of time as technologies are required and/or developed. The work discussed here illustrates how tank-by-tank databases and processing requirementsmore » have been used to generate processing sequences and time-phased deployment schedules. The processing sequences take into account requirements such as the amount and types of data available for the tanks, tank waste form and composition, required decontamination factors, and types of compact processing units (CPUS) required and technology availability. These sequences were developed from processing requirements for the tanks, which were determined from spreadsheet analyses. The spreadsheet analysis program was generated by this task in FY 1993. Efforts conducted for this task have focused on the processing requirements for Hanford double-shell tank (DST) supernatant wastes (pumpable liquid) because this waste type is easier to retrieve than the other types (saltcake and sludge), and more tank space would become available for future processing needs. The processing requirements were based on Class A criteria set by the U.S. Nuclear Regulatory Commission and Clean Option goals provided by Pacific Northwest Laboratory.« less
  • M&D Professional Services, Inc. (M&D) is under subcontract to Pacific Northwest National Laboratory (PNNL) to perform seismic analysis of the Hanford Site double-shell tanks (DSTs) in support of a project entitled ''Double-Shell Tank (DSV Integrity Project--DST Thermal and Seismic Analyses)''. The overall scope of the project is to complete an up-to-date comprehensive analysis of record of the DST system at Hanford in support of Tri-Party Agreement Milestone M-48-14, The work described herein was performed in support of the seismic analysis of the DSTs. The thermal and operating loads analysis of the DSTs is documented in Rinker et al. (2004). Themore » work statement provided to M&D (PNNL 2003) required that the seismic analysis of the DSTs assess the impacts of potentially non-conservative assumptions in previous analyses and account for the additional soil mass due to the as-found soil density increase, the effects of material degradation, additional thermal profiles applied to the full structure including the soil-structure response with the footings, the non-rigid (low frequency) response of the tank roof, the asymmetric seismic-induced soil loading, the structural discontinuity between the concrete tank wall and the support footing and the sloshing of the tank waste. The seismic analysis considers the interaction of the tank with the surrounding soil and the effects of the primary tank contents. The DSTs and the surrounding soil are modeled as a system of finite elements. The depth and width of the soil incorporated into the analysis model are sufficient to obtain appropriately accurate analytical results. The analyses required to support the work statement differ from previous analysis of the DSTs in that the soil-structure interaction (SSI) model includes several (nonlinear) contact surfaces in the tank structure, and the contained waste must be modeled explicitly in order to capture the fluid-structure interaction behavior between the primary tank and contained waste.« less
  • M&D Professional Services, Inc. (M&D) is under subcontract to Pacific Northwest National Laboratories (PNNL) to perform seismic analysis of the Hanford Site Double-Shell Tanks (DSTs) in support of a project entitled Double-Shell Tank (DST) Integrity Project - DST Thermal and Seismic Analyses. The original scope of the project was to complete an up-to-date comprehensive analysis of record of the DST System at Hanford in support of Tri-Party Agreement Milestone M-48-14. The work described herein was performed in support of the seismic analysis of the DSTs. The thermal and operating loads analysis of the DSTs is documented in Rinker et al.more » (2004). Although Milestone M-48-14 has been met, Revision I is being issued to address external review comments with emphasis on changes in the modeling of anchor bolts connecting the concrete dome and the steel primary tank. The work statement provided to M&D (PNNL 2003) required that a nonlinear soil structure interaction (SSI) analysis be performed on the DSTs. The analysis is required to include the effects of sliding interfaces and fluid sloshing (fluid-structure interaction). SSI analysis has traditionally been treated by frequency domain computer codes such as SHAKE (Schnabel, et al. 1972) and SASSI (Lysmer et al. 1999a). Such frequency domain programs are limited to the analysis of linear systems. Because of the contact surfaces, the response of the DSTs to a seismic event is inherently nonlinear and consequently outside the range of applicability of the linear frequency domain programs. That is, the nonlinear response of the DSTs to seismic excitation requires the use of a time domain code. The capabilities and limitations of the commercial time domain codes ANSYS{reg_sign} and MSC Dytran{reg_sign} for performing seismic SSI analysis of the DSTs and the methodology required to perform the detailed seismic analysis of the DSTs has been addressed in Rinker et al (2006a). On the basis of the results reported in Rinker et al. (2006a), it is concluded that time-domain SSI analysis using ANSYS{reg_sign} is justified for predicting the global response of the DSTs. The most significant difference between the current revision (Revision 1) of this report and the original issue (Revision 0) is the treatment of the anchor bolts that tie the steel dome of the primary tank to the concrete tank dome.« less