Use of Fly-Ash for Sealing a Radioactive Waste Repository

1992 ◽  
Vol 294 ◽  
Author(s):  
Marc Ollagnier ◽  
Christian Tauziede ◽  
Jodl Olivier
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Mechanical Characteristics ◽  
Hard Rock ◽  
Mining Industry ◽  
Abandoned Mines ◽  
Shaft Lining ◽  
Long Term Performance ◽  
Term Performance

ABSTRACTThe mining industry currently uses fly-ash from coal-fired power-plants to close access shafts in abandoned mines, in sedimentary formations. The technique consists of installing a plug of fly-ash, about fifty meters high, at the base of the shaft-lining. In this study, fly-ash is considered as a possible sealant for radioactive repositories in sedimentary formations, as well as in hard rock.Specific studies have been conducted in order to assess the feasibility of this technique, and to improve the long-term performance of the fly-ash seals. The hydraulic and mechanical characteristics of fly-ash, taken from the plug of an abandoned shaft, as well as from dumps of various ages, were measured. Laboratory tests showed that it is possible to reduce the hydraulic conductivity of fly-ash by a factor of thousand, with the addition of ten percent bentonite. Moreover, it seems possible to block fine fissures in the surrounding damaged rock by injecting grouts made of cement and fly-ash having maximum diameters of twenty micrometers.

Long Term Performance of PE4710 Materials in Disinfectant Treated Nuclear Raw Water Systems

2013 ◽  
Author(s):  
Alexander M. Summe ◽  
Douglas P. Munson ◽  
Kenneth Oliphant ◽  
Sarah Chung
Keyword(s):  
Power Plants ◽  
Slow Crack Growth ◽  
Life Time ◽  
Water Systems ◽  
Superior Performance ◽  
Mechanical Degradation ◽  
Service Water ◽  
Long Term Performance ◽  
Term Performance

Degradation of service water systems is a major issue facing nuclear power plants and many plants will require repair or replacement of existing carbon steel piping components. High-density polyethylene (HDPE) has been used in non-safety service water systems for over ten years and has demonstrated superior performance. However, there still exist knowledge gaps around material properties, inspectability, and long-term performance. Specifically, there is a lack of insight on the aging of HDPE piping in disinfectant treated service water systems. This paper summarizes the methodology and results of predicting the expected life time of HDPE piping exposed to oxidizing biocides in numerous end-use scenarios. The aging mechanism of concern is Stage III Chemical-Mechanical degradation, where the polymer is oxidized by biocides and then experiences slow crack growth (SCG). An Aging Model is used to provide general predictions of pipe service life. The results were analyzed for trends and limiting or sensitive operating parameters were identified. For most applications, the specific resin used in the model demonstrated good performance for lifetimes of well over 40 years.

scholarly journals INVESTIGATION TOWARDS THE LONG-RUN PERFORMANCE OF INITIAL PUBLIC OFFERINGS: EVIDENCE FROM INDONESIAN CAPITAL MARKET

2010 ◽  
Vol 2 (2) ◽  
pp. 100-125
Author(s):  
Lioniva Emasari ◽  
Dewi Tamara
Keyword(s):  
Initial Public Offerings ◽  
Abnormal Return ◽  
Mining Industry ◽  
Cumulative Abnormal Return ◽  
Public Offerings ◽  
Basic Industry ◽  
Long Run ◽  
Long Term Performance ◽  
Term Performance

We study the long-term performance of IPO share issued in Indonesia during the 1996-2001 periods. The IPOs in this period are mostly concentrated in Finance, Trade, Property and Basic Industry & Chemicals. The cumulative abnormal return (CAR) and buy-and-hold abnormal return (BHAR) in the third year are 15.83% and negative 68.02%, respectively. The CAR and BHAR in the fifth year are negative 1% and negative 139.7%, respectively. The highest CAR for 3 and 5 years are mining industry, with 289.29% and 226.80%, respectively. The lowest CAR for third year is trade, service & investment industry, with negative 59.36% and fifth year is agriculture with negative 59.72%. The lowest BHAR for third and fifth year is trade, service and investment industry with negative 113.01% and negative 230.99 respectively. The long-run performance using cumulative abnormal return is similar with the market and cannot outperform the market.  

Study on Long Term Performance of Concrete of Slag-Alkali Higher Calcium Fly Ash

2006 ◽  
Vol 302-303 ◽  
pp. 98-104
Author(s):  
Ming Tang ◽  
Xiao Li
Keyword(s):  
Fly Ash ◽  
Orthogonal Design ◽  
Concrete Specimen ◽  
Mixture Ratio ◽  
Dispersion Degree ◽  
Set Up ◽  
Long Term Performance ◽  
Term Performance ◽  
Mixture Ratio Design

The slag-alkali is used to activate the activity of higher calsium fly ash. By the designs of the mixture ratio and the quadratic regression orthogonal design, the best combination is sought out. Several mixture factors which affect the rule of the concrete material properties and long term performance are researched. The mathematic models which are set up by the mixture ratio design with the quadralic regression orthogonal design can be effective. The precision is high. The strength of the concrete of slag-alkali fly ash was still increasing after 8 year. The dispersion degree of those specimens is small. The SEM photo of cracked specimen and early concrete specimen shows the surface of fly ash in 7 days concrete is slick and that in 8 years old specimen has been enwrapped tightly by much hydrate plant.

scholarly journals Seasonal Performance Evaluation of Pavement Base Using Recycled Materials

2021 ◽  
Vol 13 (22) ◽  
pp. 12714
Author(s):  
Yang Zhang ◽  
Bora Cetin ◽  
Tuncer B. Edil
Keyword(s):  
Fly Ash ◽  
Recycled Concrete ◽  
Ride Quality ◽  
Concrete Aggregate ◽  
Traffic Loading ◽  
Pavement Base ◽  
Natural Aggregates ◽  
Long Term Performance ◽  
Term Performance

Using recycled pavement materials to construct new pavement base is currently an important construction strategy bringing improved sustainability. This study investigates the long-term performance of pavement bases constructed with recycled concrete aggregate (RCA), reclaimed asphalt pavement (RAP), and blends with natural aggregates in a seasonal frost region. The stabilization effect of fly ash on RAP was studied as well. In situ falling weight deflectometer (FWD) tests were routinely conducted to provide seasonal deflection data, which were used to back-calculate the layer modulus. Seasonal changes in the base layer modulus along with the pavement ride quality were monitored. One of the two lanes at the test sections was consistently subjected to traffic loading, whereas the other one was not. Findings from this field research indicated that after undergoing over 8 years of naturally seasonal freeze-thaw conditions, 100% RCA, 50% RCA, plus 50% natural aggregates, and 100% RAP, presented improved performance over 100% natural aggregates. However, 50% RAP blended with 50% natural aggregates performed comparably to natural aggregates only, and fly ash did not provide considerable improvement on the long-term performance of 50% RAP plus 50% natural aggregate base. Seasonal climatic variations turned out to affect pavement performance more critically than traffic loading.

Sign in / Sign up

Export Citation Format

Share Document