Use of an Offset in Assessing Radiation Embrittlement Data and Predictive Methods

2006 ◽  
Author(s):  
Naoki Soneda ◽  
Colin English ◽  
William Server
Keyword(s):  
Surveillance Data ◽  
Data Sets ◽  
Radiation Embrittlement ◽  
Constant Amount ◽  
Predictive Values ◽  
Data Scatter ◽  
The Us ◽  
Predictive Methods ◽  
Potential Use ◽  
Reactor Pressure

Analyses of reactor pressure vessel (RPV) surveillance data from Charpy V-notch shift results coupled with our latest knowledge of the mechanisms of radiation embrittlement have led to new predictive correlations/models that have a strong technical underpinning. In this paper we examine how well the new CRIEPI embrittlement predicts US RPV surveillance data. Secondly, we note that within the US surveillance data sets there are indications that the data may follow the same form as the predictive models, but the data may be offset by a constant amount (either positive or negative) from the predictive values. This offset can be attributed in some cases to inadequate baseline data. In other cases, there does not appear to be a constant offset, or such an offset is hidden by data scatter. This paper also reviews the potential use of an offset adjustment and focuses on several surveillance datasets for comparisons.

scholarly journals Nanostructure Self-Organization as Cause of Wavelike Radiation Embrittlement of the RPV Steel

2017 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Self Organization ◽  
Radiation Embrittlement ◽  
Neutron Bombardment ◽  
Rpv Steel ◽  
Radiation Degradation ◽  
Data Scatter ◽  
Metal Nanostructure ◽  
Normative Value ◽  
Reactor Pressure ◽  
Dose Rate Effect

Influence of neutron irradiation on reactor pressure vessel (RPV) steel degradation are examined with reference to the possible reasons of the substantial experimental data scatter and furthermore-nonstandard (non-monotonous) and oscillatory embrittlement behavior. In our glance this phenomenon may be explained by presence of the wavelike recovering component in the embrittlement kinetics. In our opinion controversy in the estimation on neutron flux on radiation degradation impact may be explained by presence of the wavelike component in the embrittlement kinetics. Therefore flux effect manifestation depends on fluence level. At low fluencies radiation degradation has to exceed normative value, then approaches to normative meaning and finally became sub normative. As a result of dose rate effect manifestation peripheral RPV’s zones in some range of fluencies have to be damaged to a large extent than situated closely to core. Moreover as a hypothesis we suppose that at some stages of irradiation damaged metal have to be partially restored by irradiation i.e. neutron bombardment. Nascent during irradiation nanostructure undergo occurring once or periodically evolution in a direction both degradation and recovery of the initial properties. According to our hypothesis at some stage(s) of metal nanostructure degradation neutron bombardment became recovering factor. As a result oscillation arise that in tern lead to enhanced data scatter. In this case we have to consider irradiation as a recovery factor. Disclosure of the steel degradation oscillating is a sign of the steel nanostructure cyclic self-recovery transformation as it take place in self-organization processes.

Analyst Performance Measures. Volume 2: Information Quality Tools for Persistent Surveillance Data Sets

2011 ◽  
Author(s):  
Marina Altynova ◽  
Ed Wasser ◽  
Telford Berkey ◽  
Sanjay Boddhu ◽  
Tin Sa ◽  
...  
Keyword(s):  
Performance Measures ◽  
Information Quality ◽  
Surveillance Data ◽  
Data Sets ◽  
Quality Tools

scholarly journals Using Markov Chains to Predict Productivity of Maize in Iraq for the Period (2019-2025)

2021 ◽  
Vol 8 (5) ◽  
pp. 1
Author(s):  
L.A.F. Al-Ani ◽  
A.D.K. Alhiyali
Keyword(s):  
Markov Chains ◽  
Historical Data ◽  
Unit Area ◽  
Recent Past ◽  
Predictive Values ◽  
The Third ◽  
Predictive Methods ◽  
Horizontal Expansion ◽  
Predicted Values ◽  
The Impact

The research aims to predict the productivity of one of the most important major crops in Iraq, which is Maize, using Markov chains, which is one of the most important predictive methods that depend on relatively recent historical data and based mainly on previous data that is not far away. This is the advantage that Markov chains have, as relying on somewhat old historical data may negatively affect the predicted values. The results of the research showed the superiority of the third state to predict the productivity of Maize depending on the availability of Markov chains prediction conditions for this state. The results of the research also showed the continued decline in productivity for the coming years, as well as the impact of the predictive values on changes in the cultivated area more than changes in production, which confirms the existence of horizontal expansion at the expense of vertical expansion, that is, there is no intensification of production per unit area. The research also found that the actual values of productivity have approached the estimated values of the following years, and the matter applies to the convergence of these results for the subsequent years with the previous years, which confirms the accuracy of the method of Markov chains, in other words that what happened in the recent past had a clear impact in the future near.

scholarly journals What are the implications of using individual and combined sources of routinely collected data to identify and characterise incident site-specific cancers? a concordance and validation study using linked English electronic health records data

BMJ Open ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. e037719
Author(s):  
Helen Strongman ◽  
Rachael Williams ◽  
Krishnan Bhaskaran
Keyword(s):  
Primary Care ◽  
Gold Standard ◽  
Cancer Registration ◽  
Data Sets ◽  
Death Registration ◽  
Case Definitions ◽  
Predictive Values ◽  
Site Specific ◽  
Registration Data ◽  
Electronic Health

ObjectivesTo describe the benefits and limitations of using individual and combinations of linked English electronic health data to identify incident cancers.Design and settingOur descriptive study uses linked English Clinical Practice Research Datalink primary care; cancer registration; hospitalisation and death registration data.Participants and measuresWe implemented case definitions to identify first site-specific cancers at the 20 most common sites, based on the first ever cancer diagnosis recorded in each individual or commonly used combination of data sources between 2000 and 2014. We calculated positive predictive values and sensitivities of each definition, compared with a gold standard algorithm that used information from all linked data sets to identify first cancers. We described completeness of grade and stage information in the cancer registration data set.Results165 953 gold standard cancers were identified. Positive predictive values of all case definitions were ≥80% and ≥94% for the four most common cancers (breast, lung, colorectal and prostate). Sensitivity for case definitions that used cancer registration alone or in combination was ≥92% for the four most common cancers and ≥80% across all cancer sites except bladder cancer (65% using cancer registration alone). For case definitions using linked primary care, hospitalisation and death registration data, sensitivity was ≥89% for the four most common cancers, and ≥80% for all cancer sites except kidney (69%), oral cavity (76%) and ovarian cancer (78%). When primary care or hospitalisation data were used alone, sensitivities were generally lower and diagnosis dates were delayed. Completeness of staging data in cancer registration data was high from 2012 (minimum 76.0% in 2012 and 86.4% in 2014 for the four most common cancers).ConclusionsAscertainment of incident cancers was good when using cancer registration data alone or in combination with other data sets, and for the majority of cancers when using a combination of primary care, hospitalisation and death registration data.

scholarly journals Firearm-Related Deaths in Multnomah County, Oregon, 2010-2016: Linking Medical Examiner Data to State Vital Records Data

2019 ◽  
Vol 135 (1) ◽  
pp. 40-46
Author(s):  
Jaime Walters
Keyword(s):  
Race And Ethnicity ◽  
Public Health Problem ◽  
Medical Examiner ◽  
Data Sets ◽  
Data Systems ◽  
Manner Of Death ◽  
Predictive Values ◽  
Multnomah County ◽  
Routine Surveillance ◽  
Vital Records

Objectives: Violence due to firearms is a substantial public health problem. Death data from medical examiner and vital records were linked to evaluate the use of medical examiner data to augment routine surveillance and determine any differences in sex, age, manner of death, or race and ethnicity between the 2 data systems. Materials and Methods: Medical examiner data were searched for keywords of interest, and vital records data were obtained and linked for deaths occurring in Multnomah County, Oregon, from January 1, 2010, through December 31, 2016. Both data sets were compared for the number and proportion of firearm-related deaths by sex, age, manner of death, and race/ethnicity. Sensitivity and positive predictive values were calculated for variables that had discordant results. Results: A total of 568 firearm-related deaths were identified in the medical examiner data. After matching with manual review, the 2 data systems had 100% case agreement. A reverse match showed that most cases not found in medical examiner data were due to transfer of case jurisdiction. The 2 systems matched nearly perfectly in sex, age, and manner of death but differed in characterization of race and ethnicity. Sensitivity was 62% for Hispanic ethnicity but 93% for white and black race. Practice Implications: Using medical examiner data was a useful way to augment routine surveillance of firearm-related deaths in our jurisdiction in close to real time. However, caution is needed when analyzing data by subgroups because of discordant classifications of race between the data systems.

Use of Enterobacteriaceae Analysis Results for Predicting Absence of Salmonella Serovars on Beef Carcasses

2009 ◽  
Vol 72 (2) ◽  
pp. 260-266 ◽  
Author(s):  
JOHN R. RUBY ◽  
STEVEN C. INGHAM
Keyword(s):  
Small Volume ◽  
Large Data ◽  
Data Sets ◽  
Data Set ◽  
A Value ◽  
Large Data Set ◽  
Intervention Treatment ◽  
Beef Carcasses ◽  
Predictive Approach ◽  
Potential Use

Previous work using a large data set (no. 1, n = 5,355) of carcass sponge samples from three large-volume beef abattoirs highlighted the potential use of binary (present or absent) Enterobacteriaceae results for predicting the absence of Salmonella on carcasses. Specifically, the absence of Enterobacteriaceae was associated with the absence of Salmonella. We tested the accuracy of this predictive approach by using another large data set (no. 2, n = 2,163 carcasses sampled before or after interventions) from the same three data set no. 1 abattoirs over a later 7-month period. Similarly, the predictive approach was tested on smaller subsets from data set no. 2 (n = 1,087, and n = 405) and on a much smaller data set (no. 3, n = 100 postintervention carcasses) collected at a small-volume abattoir over 4 months. Of Enterobacteriaceae-negative data set no. 2 carcasses, >98% were Salmonella negative. Similarly accurate predictions were obtained in the two data subsets obtained from data set no. 2 and in data set no. 3. Of final postintervention carcass samples in data set nos. 2 and 3, 9 and 70%, respectively, were Enterobacteriaceae positive; mean Enterobacteriaceae values for the two data sets were −0.375, and 0.169 log CFU/100 cm2 (detection limit = −0.204, and Enterobacteriaceae negative assigned a value of −0.505 log CFU/100 cm2). Salmonella contamination rates for final postintervention beef carcasses in data set nos. 2 and 3 were 1.1 and 7.0%, respectively. Binary Enterobacteriaceae results may be useful in evaluating beef abattoir hygiene and intervention treatment efficacy.

Characteristics of the New Embrittlement Correlation Method for the Japanese Reactor Pressure Vessel Steels

2009 ◽  
Author(s):  
Naoki Soneda ◽  
Akiyoshi Nomoto
Keyword(s):  
Pressure Vessel ◽  
Correlation Method ◽  
Reactor Pressure Vessel ◽  
Surveillance Data ◽  
New Method ◽  
Rate Equations ◽  
Mathematical Form ◽  
Microstructural Changes ◽  
Pressure Vessel Steels ◽  
Reactor Pressure

Neutron irradiation embrittlement of reactor pressure vessel steels is an important ageing issue for the long term operation of light water reactors. A new embrittlement correlation method was developed by CRIEPI and the Japanese electric utilities in 2007. This method is primarily based on the fundamental understandings on the embrittlement mechanisms: i.e. microstructural changes were modeled by the mathematical form of rate equations, and the predicted microstructural changes were further correlated with the mechanical property changes in transition temperature region. The coefficients of the rate equations were optimized using the Japanese surveillance data of RPV embrittlement. This method was adopted as the revision of the Japanese code, JEAC 4201–2007, in 2007. In this paper, after a brief explanation on the new correlation method, the predictions of the new method will be investigated through comparisons with the previous correlation, JEAC4201–2004, and the US surveillance data in order to identify the characteristics of the new method.

Fracture Mechanics Assessment of Reactor Pressure Vessel Irradiated Structural Steel for Short Column Type Supports and Neutron Shield Tank

2020 ◽  
Author(s):  
Alexandria M. Carolan ◽  
J. Brian Hall ◽  
Stephen K. Longwell ◽  
F. Arzu Alpan ◽  
Gregory M. Imbrogno ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Structural Steel ◽  
Pressure Vessel ◽  
Radiation Effects ◽  
Structural Integrity ◽  
Reactor Pressure Vessel ◽  
Radiation Embrittlement ◽  
Short Column ◽  
License Renewal ◽  
Reactor Pressure

Abstract As plants apply for 80 year licensure (subsequent license renewal), the United States Nuclear Regulatory Commission (U.S. NRC) has queried the nuclear power plant industry to investigate the impact of neutron embrittlement (radiation effects) on the reactor pressure vessel (RPV) structural steel supports due to extended plant operation past 60 years. The radiation effects on RPV supports were previously investigated and resolved as part of Generic Safety Issue No. 15 (GSI-15) in NUREG-0933 Revision 3 [1], NUREG-1509 [2] (published in May 1996), and NUREG/CR-5320 [3] (published in January 1989) for design life (40 years) and for first license renewal (20 additional years). The conclusions in NUREG-0933, Revision 3 stated that there were no structural integrity concerns for the RPV support structural steels; even if all the supports were totally removed (i.e. broken), the piping has acceptable margin to carry the load of the vessel. Nevertheless, for plants applying for 80 year life licensure, the U.S. NRC has requested an evaluation to show structural integrity of the RPV supports by accounting for radiation embrittlement (radiation damage) for continued operation into the second license renewal period (i.e. 80 years). The RPV support designs in light water reactors are grouped into one of five categories or types of supports: (1) skirt; (2) long-column; (3) shield-tank; (4) short column; and (5) suspension. In this paper, two of these RPV support configurations (short column supports and neutron shield tank) will be investigated using fracture mechanics to evaluate the effect of radiation embrittlement of the structural steel supports for long term operations (i.e. 80 years). The technical evaluation of other support configurations will be provided in a separate technical publication at a future date.

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