Safety Analysis and Comparison of Toxicities for the Disposal of Radioactive Waste of Negligible Heat Generation Including Transuranic Elements

1988 ◽  
Vol 127 ◽  
Author(s):  
H. P. Berg ◽  
D. Ehrlich ◽  
B. Thomauske
Keyword(s):  
Radioactive Waste ◽  
Heat Generation ◽  
Safety Analysis ◽  
Activity Limitations ◽  
Natural Toxicity ◽  
Operational Phase

ABSTRACTRequirements on radioactive waste of negligible heat generation with respect to transuranic elements, derived from the safety analysis of the operational phase of the Konrad repository, are described and resulting activity limitations are discussed. For assessing the long term safety, the calculation of individual doses in connection with the very slow water movements and, additionally, toxicity comparisons to other waste and to the natural toxicity at the site are discussed. Some information is given on the procedure of taking into account the activity limitations in an optimal way when planning emplacement campaigns.

Planning to 'remember to forget'?

2012 ◽  
Vol 76 (8) ◽  
pp. 3491-3496 ◽  
Author(s):  
S. Mobbs
Keyword(s):  
Radioactive Waste ◽  
Early Stage ◽  
Management Control ◽  
Regulatory Control ◽  
The Future ◽  
Passive Management ◽  
Operational Phase ◽  
Geological Formations ◽  
Far Future

AbstractDisposal in deep geological formations aims to provide isolation of long-lived radioactive waste for hundreds of thousands of years. This raises the question of the long-term governance of the repository throughout its lifetime. In the operational phase the repository is under active regulatory control. Once closed, there will be a phase of passive management control or indirect oversight. This will be followed, at some time in the future, by a period in which there is no oversight. This may be a result of a decision to cease management control or it may occur through loss of records or a change in priorities. The importance of the main exposure scenarios (exposure as a result of the gradual transport of radionuclides in groundwater, transport of radionuclides in gas, and exposure arising from inadvertent intrusion into the repository) are discussed with reference to these different phases. An interesting question is 'How do we minimize the risk of inadvertent intrusion in the far future?' Perhaps it is better to ensure that the repository is forgotten and should we try to plan for this? The different approaches are discussed and the importance of deciding on a strategy at an early stage is emphasized.

Development and Analysis of Scenarios for a Permanent Repository for Radioactive Wastes in Salt Rock

2000 ◽  
Vol 663 ◽  
Author(s):  
S. Keller
Keyword(s):  
Radioactive Waste ◽  
Conceptual Model ◽  
Safety Assessment ◽  
Safety Analysis ◽  
Radioactive Wastes ◽  
Specific Site ◽  
Salt Rock

ABSTRACTScenarios were developed and analyzed as part of a long-term safety analysis of a permanent repository for radioactive wastes. A procedure is described by which features, events, and processes (FEP) at a specific site can be evaluated for the long-term safety assessment of a permanent repository for radioactive waste. These FEPs can be weighted according to selected criteria and combined to scenarios using a conceptual model of the site.

An Assessment of the Long-Term Durability of Concrete in Radioactive Waste Repositories

1985 ◽  
Vol 50 ◽  
Author(s):  
A. Atkinson ◽  
D. J. Goult ◽  
J. A. Hearne
Keyword(s):  
Reinforced Concrete ◽  
Radioactive Waste ◽  
Concrete Slab ◽  
Laboratory Studies ◽  
Preliminary Assessment ◽  
Reinforced Concrete Slab ◽  
Radioactive Waste Repositories ◽  
Waste Repositories ◽  
Durability Of Concrete

AbstractA preliminary assessment of the long-term durability of concrete in a repository sited in clay is presented. The assessment is based on recorded experience of concrete structures and both field and laboratory studies. It is also supported by results of the examination of a concrete sample which had been buried in clay for 43 years.The enoineering lifetime of a 1 m thick reinforced concrete slab, with one face in contact with clay, and the way in which pH in the repository as a whole is likely to vary with time have both been estimated from available data. The estimates indicate that engineering lifetimes of about 103 years are expected (providing that sulphate resisting cement is used) and that pH is likely to remain above 10.5 for about 106 years.

Coupled transport-reaction modeling of the long-term interaction between iron, bentonite and Callovo-Oxfordian claystone in radioactive waste confinement systems

2014 ◽  
Vol 101 ◽  
pp. 430-443 ◽  
Author(s):  
Viet V. Ngo ◽  
Manuella Delalande ◽  
Alain Clément ◽  
Nicolas Michau ◽  
Bertrand Fritz
Keyword(s):  
Radioactive Waste ◽  
Coupled Transport ◽  
Transport Reaction

scholarly journals Intervertebral disc therapies for non-specific chronic low back pain: a systematic review and meta-analysis

2021 ◽  
Vol 13 ◽  
pp. 1759720X2110280
Author(s):  
Camille Daste ◽  
Stéphanie Laclau ◽  
Margaux Boisson ◽  
François Segretin ◽  
Antoine Feydy ◽  
...  
Keyword(s):  
Systematic Review ◽  
Low Back Pain ◽  
Back Pain ◽  
Intervertebral Disc ◽  
Chronic Low Back Pain ◽  
Meta Analysis ◽  
Activity Limitations ◽  
Low Back ◽  
Short Term

Objectives: We aim to evaluate the benefits and harms of intervertebral disc therapies (IDTs) in people with non-specific chronic low back pain (NScLBP). Methods: We conducted a systematic review and meta-analysis of randomized trials of IDTs versus placebo interventions, active comparators or usual care. EMBASE, MEDLINE, CENTRAL and CINHAL databases and conference abstracts were searched from inception to June 2020. Two independent investigators extracted data. The primary outcome was LBP intensity at short term (1 week–3 months), intermediate term (3–6 months) and long term (after 6 months). Results: Of 18 eligible trials (among 1396 citations), five assessed glucocorticoids (GCs) IDTs and were included in a quantitative synthesis; 13 assessed other products including etanercept ( n = 2), tocilizumab ( n = 1), methylene blue ( n = 2), ozone ( n = 2), chymopapaine ( n = 1), glycerol ( n = 1), stem cells ( n = 1), platelet-rich plasma ( n = 1) and recombinant human growth and differentiation factor-5 ( n = 2), and were included in a narrative synthesis. Standardized mean differences (95% CI) for GC IDTs for LBP intensity and activity limitations were −1.33 (−2.34; −0.32) and −0.76 (−1.85; 0.34) at short term, −2.22 (−5.34; 0.90) and −1.60 (−3.51; 0.32) at intermediate term and −1.11 (−2.91; 0.70) and −0.63 (−1.68; 0.42) at long term, respectively. Odds ratios (95% CI) for serious and minor adverse events with GC IDTs were 1.09 (0.25; 4.65) and 0.97 (0.49; 1.91). Conclusion: GC IDTs are associated with a reduction in LBP intensity at short term in people with NScLBP. Positive effects are not sustained. IDTs have no effect on activity limitations. Our conclusions are limited by high heterogeneity and a limited methodological quality across studies. Registration PROSPERO: CRD42019106336.

Long-Term Simulation of Sodium Dynamics During a Large Leakage Sodium-Water Reaction

2021 ◽  
Author(s):  
Xi Bai ◽  
Peiwei Sun ◽  
Gang Luo ◽  
Huasong Cao
Keyword(s):  
Steam Generator ◽  
Safety Analysis ◽  
Euler Method ◽  
Maximum Pressure ◽  
Parameter Method ◽  
Loop Model ◽  
Long Term Effects ◽  
Water Steam ◽  
Secondary Loop

Abstract The steam generator of the sodium-cooled reactor is the barrier between the secondary and third loops. When the heat transfer pipe breaks, the water/steam will pour into the sodium and a sodium-water reaction will occur. The pressure in the secondary loop will increase and the rupture disks will burst to reduce the pressure. For the safety analysis, the maximum pressure is limited. For the long term, the pressure pulse weakens and the fluid flow tends to a quasi-steady state several seconds or minutes after leak initiation. Therefore, it is necessary to develop a model to investigate the dynamics of the secondary loop in the long term. The continuity equation, the momentum equation and the energy equation are used to derive the sodium flow model in the secondary loop. The sodium pressure and velocity are described by the one-dimensional differential equation. The lumped parameter method is applied and the differential equations are solved by the Euler method. FORTRAN language is compiled to develop the code. Critical equipment, including the steam generator, buffer tank, pump, rupture disks, and accident discharge tank are considered in the secondary loop model. The sodium velocity and pressure responses varying with time can be obtained. Compared with the data from the safety analysis report, the tendency of the sodium velocity and pressure is consistent. It is proved that the model is reasonable and effective to simulate and analyze the actual long-term effects of sodium dynamics.

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