Standard Guide for Predicting Radiation-Induced Transition Temperature Shift in Reactor Vessel Materials
NORMA vydaná dňa 1.2.2015
Označenie normy: ASTM E900-15e1
Dátum vydania normy: 1.2.2015
Počet strán: 5
Približná hmotnosť: 15 g (0.03 libier)
Krajina: Americká technická norma
Kategória: Technické normy ASTM
ICS Number Code 27.120.10 (Reactor engineering)
Adjunct for E900-15 Technical Basis for the Equation Used to Predict Radiation-Induced Transition Temperature Shift in Reactor Vessel MaterialsVybraný formát:
Adjunct for E900-15 Technical Basis for the Equation Used to Predict Radiation-Induced Transition Temperature Shift in Reactor Vessel Materials + Active StandardVybraný formát:
|Significance and Use|
4.1 Operation of commercial power reactors must conform to pressure-temperature limits during heatup and cooldown to prevent over-pressurization at temperatures that might cause non-ductile behavior in the presence of a flaw. Radiation damage to the reactor vessel is compensated for by adjusting the pressure-temperature limits to higher temperatures as the neutron damage accumulates. The present practice is to base that adjustment on the TTS produced by neutron irradiation as measured at the Charpy V-notch 41-J (30-ft·lbf) energy level. To establish pressure temperature operating limits during the operating life of the plant, a prediction of TTS must be made.
4.1.1 In the absence of surveillance data for a given reactor material (see Practice and ), the use of calculative procedures are necessary to make the prediction. Even when credible surveillance data are available, it will usually be necessary to interpolate or extrapolate the data to obtain a TTS for a specific time in the plant operating life. The embrittlement correlation presented herein has been developed for those purposes.
4.2 Research has established that certain elements, notably copper (Cu), nickel (Ni), phosphorus (P), and manganese (Mn), cause a variation in radiation sensitivity of reactor pressure vessel steels. The importance of other elements, such as silicon (Si), and carbon (C), remains a subject of additional research. Copper, nickel, phosphorus, and manganese are the key chemistry parameters used in developing the calculative procedures described here.
4.3 Only power reactor (PWR and BWR) surveillance data were used in the derivation of these procedures. The measure of fast neutron fluence used in the procedure is n/m2 (E > 1 MeV). Differences in fluence rate and neutron energy spectra experienced in power reactors and test reactors have not been accounted for in these procedures.
1.1 This guide presents a method for predicting values of reference transition temperature shift (1.1.1 The range of material and irradiation conditions in the database for variables used in the embrittlement correlation:
188.8.131.52 Copper content up to 0.4 %.
184.108.40.206 Nickel content up to 1.7 %.
220.127.116.11 Phosphorus content up to 0.03 %.
18.104.22.168 Manganese content within the range from 0.55 to 2.0 %.
22.214.171.124 Irradiation temperature within the range from 255 to 300°C (491 to 572°F).
126.96.36.199 Neutron fluence within the range from 1 × 1021 n/m2 to 2 × 1024 n/m2 (E> 1 MeV).
188.8.131.52 A categorical variable describing the product form (that is, weld, plate, forging).
1.1.2 The range of material and irradiation conditions in the database for variables not included in the embrittlement correlation:
184.108.40.206 Type B Class 1 and 2, Grade B, Grade B (modified), and Class 2 and 3. Also, European and Japanese steel grades that are equivalent to these ASTM Grades.
220.127.116.11 Submerged arc welds, shielded arc welds, and electroslag welds having compositions consistent with those of the welds used to join the base materials described in .
18.104.22.168 Neutron fluence rate within the range from 3 × 1012 n/m2/s to 5 × 1016 n/m2/s (E > 1 MeV).
22.214.171.124 Neutron energy spectra within the range expected at the reactor vessel region adjacent to the core of commercial PWRs and BWRs (greater than approximately 500MW electric).
126.96.36.199 Irradiation exposure times of up to 25 years in boiling water reactors and 31 years in pressurized water reactors.
1.2 It is the responsibility of the user to show that the conditions of interest in their application of this guide are addressed adequately by the technical information on which the guide is based. It should be noted that the conditions quantified by the database are not distributed evenly over the range of materials and irradiation conditions described in , and that some combination of variables, particularly at the extremes of the data range are under-represented. Particular attention is warranted when the guide is applied to conditions near the extremes of the data range used to develop the TTS equation and when the application involves a region of the data space where data is sparse. Although the embrittlement correlation developed for this guide was based on statistical analysis of a large database, prudence is required for applications that involve variable values beyond the ranges specified in . Due to strong correlations with other exposure variables within the database (that is, fluence), and due to the uneven distribution of data within the database (for example, the irradiation temperature and flux range of PWR and BWR data show almost no overlap) neither neutron fluence rate nor irradiation time sufficiently improved the accuracy of the predictions to merit their use in the embrittlement correlation in this guide. Future versions of this guide may incorporate the effect of neutron fluence rate or irradiation time, or both, on 1.3 This guide is expected to be used in coordination with several standards addressing irradiation surveillance of light-water reactor vessel materials. Method of determining the applicable fluence for use in this guide are addressed in Guides , , and Test Method . The overall application of these separate guides and practices is described in Practice .
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to U.S. Customary units that are provided for information only and are not considered standard.
1.5 This standard guide does not define how the 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
|2. Referenced Documents|
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