This paper provides a possible approach for incorporating probabilistic structural integrity asse... more This paper provides a possible approach for incorporating probabilistic structural integrity assessment which is sufficiently simple to encourage its adoption by design engineers. The approach, called the “Three-Term Reference Damage Model (3T-RDM)”, is developed in the context of a particular benchmark problem and a proposed Design Chart where the probability of crack initiation by creep-fatigue in a widely used material in nuclear plants, namely 316H austenitic stainless steel, is estimated based on the R5V2/3 high temperature procedure. In principle, the 3T-RDM is not restricted to a particular failure mechanism, i.e., fracture, creep rupture, creep-fatigue crack initiation and growth are all within its scope, and non-metallic materials may also be addressed. To further validate the accuracy and generality of the proposed
3T-RDM and Design Chart, deterministic and Monte Carlo probabilistic structural integrity assessments are conducted for three EDF nuclear plant case-studies and the results are superimposed on the Design Chart obtained from the benchmark problem. The analysis indicates an excellent consistency between the results, justifying the adoption of the 3T-RDM for an intermediate level of probabilistic assessment in the nuclear sector.
Deterministic structural assessments in the creep regime are subject to large uncertainties due t... more Deterministic structural assessments in the creep regime are subject to large uncertainties due to the intrinsic scatter in creep data and the sensitivity of creep to both temperature and stress, parameters which may also be very uncertain in plant applications. Where bounding assumptions provide a clear assurance of structural integrity, traditional deterministic approaches may be perfectly adequate. Where this is not the case, the engineer may have difficulty determining whether the lack of a deterministic margin is indicative of a real threat to the plant or simply an artefact of multiple conservatisms. This can be addressed by a probabilistic assessment which will quantify the degree of threat. Moreover, bounding deterministic assessments are of little utility in cases where individual components have already failed, for example in boilers where small numbers of tube leaks are to be expected over plant life. The objective in such cases is not avoidance of any failures, but manag...
A list of references is provided for sources of data on mispaternity rates worldwide. The term "m... more A list of references is provided for sources of data on mispaternity rates worldwide. The term "mispaternity", a contraction of misattributed paternity, is used here to denote cases where a putative father is revealed by biochemical testing not to be the father. Sources generally refer to this as "paternity exclusion" and the term "mispaternity" is used here as synonymous. Mispaternity rates depend extremely sensitively on two things: firstly on demographic, and secondly on whether there is disputed paternity or suspicions about paternity before testing. Consequently, there is a huge spread of measured mispaternity rates and this has contributed to controversy on the subject. It is likely that mispaternity rates will differ by more than an order of magnitude between the highest and lowest socioeconomic groups.
In this article I examine briefly what is being done to encourage women to take up STEM subjects ... more In this article I examine briefly what is being done to encourage women to take up STEM subjects and professions in which they are the minority. Specifically I concentrate on mechanical engineering and physics. My purpose is to contrast this with what is being done to encourage men into a profession in which they are the minority, namely teaching. I find that the male dominated engineering and physics professions are energetically and positively involved in actively encouraging women into their professions. The contrast between this and what men face in the teaching profession could not be more stark. In the teaching unions there is no recognition whatsoever that men, a dwindling minority, deserve any assistance or encouragement at all. In all the decades in which the male dominated engineering and physics professions have been fully engaged in actively assisting women, there has been no reciprocation whatsoever from the teaching profession in encouraging male teachers. The opposite is the case: the teaching unions have continued to promote and assist women, their dominant constituency, at the expense of men. The searches conducted for this article were carried out in January 2015.
In the 7 years 2009 to 2015, inclusive, there were 332 children culpably killed in the UK whose d... more In the 7 years 2009 to 2015, inclusive, there were 332 children culpably killed in the UK whose deaths have been subject to Serious Case Reviews by the child protection authorities (excluding suicides). A review of information gleaned from these Serious Case Reviews (SCRs) is presented here. The perpetrators of child killings in the UK is not reported in ONS data. This review serves to identify the perpetrators of child killings in the UK. Formal homicide data may not record all these child deaths since some are not recorded as homicides.
This paper provides a possible approach for incorporating probabilistic structural integrity asse... more This paper provides a possible approach for incorporating probabilistic structural integrity assessment which is sufficiently simple to encourage its adoption by design engineers. The approach, called the “Three-Term Reference Damage Model (3T-RDM)”, is developed in the context of a particular benchmark problem and a proposed Design Chart where the probability of crack initiation by creep-fatigue in a widely used material in nuclear plants, namely 316H austenitic stainless steel, is estimated based on the R5V2/3 high temperature procedure. In principle, the 3T-RDM is not restricted to a particular failure mechanism, i.e., fracture, creep rupture, creep-fatigue crack initiation and growth are all within its scope, and non-metallic materials may also be addressed. To further validate the accuracy and generality of the proposed
3T-RDM and Design Chart, deterministic and Monte Carlo probabilistic structural integrity assessments are conducted for three EDF nuclear plant case-studies and the results are superimposed on the Design Chart obtained from the benchmark problem. The analysis indicates an excellent consistency between the results, justifying the adoption of the 3T-RDM for an intermediate level of probabilistic assessment in the nuclear sector.
Deterministic structural assessments in the creep regime are subject to large uncertainties due t... more Deterministic structural assessments in the creep regime are subject to large uncertainties due to the intrinsic scatter in creep data and the sensitivity of creep to both temperature and stress, parameters which may also be very uncertain in plant applications. Where bounding assumptions provide a clear assurance of structural integrity, traditional deterministic approaches may be perfectly adequate. Where this is not the case, the engineer may have difficulty determining whether the lack of a deterministic margin is indicative of a real threat to the plant or simply an artefact of multiple conservatisms. This can be addressed by a probabilistic assessment which will quantify the degree of threat. Moreover, bounding deterministic assessments are of little utility in cases where individual components have already failed, for example in boilers where small numbers of tube leaks are to be expected over plant life. The objective in such cases is not avoidance of any failures, but manag...
A list of references is provided for sources of data on mispaternity rates worldwide. The term "m... more A list of references is provided for sources of data on mispaternity rates worldwide. The term "mispaternity", a contraction of misattributed paternity, is used here to denote cases where a putative father is revealed by biochemical testing not to be the father. Sources generally refer to this as "paternity exclusion" and the term "mispaternity" is used here as synonymous. Mispaternity rates depend extremely sensitively on two things: firstly on demographic, and secondly on whether there is disputed paternity or suspicions about paternity before testing. Consequently, there is a huge spread of measured mispaternity rates and this has contributed to controversy on the subject. It is likely that mispaternity rates will differ by more than an order of magnitude between the highest and lowest socioeconomic groups.
In this article I examine briefly what is being done to encourage women to take up STEM subjects ... more In this article I examine briefly what is being done to encourage women to take up STEM subjects and professions in which they are the minority. Specifically I concentrate on mechanical engineering and physics. My purpose is to contrast this with what is being done to encourage men into a profession in which they are the minority, namely teaching. I find that the male dominated engineering and physics professions are energetically and positively involved in actively encouraging women into their professions. The contrast between this and what men face in the teaching profession could not be more stark. In the teaching unions there is no recognition whatsoever that men, a dwindling minority, deserve any assistance or encouragement at all. In all the decades in which the male dominated engineering and physics professions have been fully engaged in actively assisting women, there has been no reciprocation whatsoever from the teaching profession in encouraging male teachers. The opposite is the case: the teaching unions have continued to promote and assist women, their dominant constituency, at the expense of men. The searches conducted for this article were carried out in January 2015.
In the 7 years 2009 to 2015, inclusive, there were 332 children culpably killed in the UK whose d... more In the 7 years 2009 to 2015, inclusive, there were 332 children culpably killed in the UK whose deaths have been subject to Serious Case Reviews by the child protection authorities (excluding suicides). A review of information gleaned from these Serious Case Reviews (SCRs) is presented here. The perpetrators of child killings in the UK is not reported in ONS data. This review serves to identify the perpetrators of child killings in the UK. Formal homicide data may not record all these child deaths since some are not recorded as homicides.
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Papers by Rick Bradford
3T-RDM and Design Chart, deterministic and Monte Carlo probabilistic structural integrity assessments are conducted for three EDF nuclear plant case-studies and the results are superimposed on the Design Chart obtained from the benchmark problem. The analysis indicates an excellent consistency between the results, justifying the adoption of the 3T-RDM for an intermediate level of probabilistic assessment in the nuclear sector.
Drafts by Rick Bradford
3T-RDM and Design Chart, deterministic and Monte Carlo probabilistic structural integrity assessments are conducted for three EDF nuclear plant case-studies and the results are superimposed on the Design Chart obtained from the benchmark problem. The analysis indicates an excellent consistency between the results, justifying the adoption of the 3T-RDM for an intermediate level of probabilistic assessment in the nuclear sector.