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Standard Test Method for Application and Analysis of Helium Accumulation Fluence Monitors for Reactor Vessel Surveillance, E706 (IIIC)
Automatische name übersetzung:
Standard-Testverfahren bei der Verarbeitung und Analyse von Helium Accumulation Fluence Monitore für Reaktor Schiff Surveillance, E706 (IIIC)
NORM herausgegeben am 1.1.2013
Bezeichnung normen: ASTM E910-07(2013)
Anmerkung: UNGÜLTIG
Ausgabedatum normen: 1.1.2013
SKU: NS-48449
Zahl der Seiten: 12
Gewicht ca.: 36 g (0.08 Pfund)
Land: Amerikanische technische Norm
Kategorie: Technische Normen ASTM
Keywords:
ICS Number Code 17.240 (Radiation measurements)
Significance and Use | ||||
5.1 The HAFM test method is one of several available passive neutron dosimetry techniques (see, for example, Methods E854 and E1005). This test method can be used in combination with other dosimetry methods, or, if sufficient data are available from different HAFM sensor materials, as an alternative dosimetry test method. The HAFM method yields a direct measurement of total helium production in an irradiated sample. Absolute neutron fluence can then be inferred from this, assuming the appropriate spectrum integrated total helium production cross section. Alternatively, a calibration of the composite neutron detection efficiency for the HAFM method may be obtained by exposure in a benchmark neutron field where the fluence and spectrum averaged cross section are both known (see Matrix E706 IIE). 5.2 HAFMs have the advantage of producing an end product, helium, which is stable, making the HAFM method very attractive for both short-term and long-term fluence measurements without requiring time-dependent corrections for decay. HAFMs are therefore ideal passive, time-integrating fluence monitors. Additionally, the burnout of the daughter product, helium, is negligible. 5.2.1 Many of the HAFM materials can be irradiated in the form of unencapsulated wire segments (see HAFM Sensor Material |
Principal Helium Producing Reaction |
Thermal Neutron Cross Section, (b) |
Fission Neutron Spectrum |
|
Cross Section, (mb)A |
90 % Response |
|||
Li |
6Li(n,α)T |
942 |
457 |
0.167–5.66 |
Be |
9Be(n,α)6He ;ra 6Li |
... |
284 |
2.5–7.3 |
B |
10B(n,α)7Li |
3838 |
494 |
0.066–5.25 |
N |
14N(n,α)11B |
... |
86.2 |
1.7–5.7 |
F |
19F(n,α)16N |
... |
27.6 |
3.7–9.7 |
AlB |
27Al(n,α)24Na |
... |
0.903 |
6.47–11.9 |
S |
32S(n,α)29Si |
... |
... |
... |
Cl |
35Cl(n,α)32P |
... |
∼13 (Cl) |
2.6–8.3 |
TiB |
47Ti(n,α)44Ca |
... |
0.634 (Ti) |
6.5–12.8 |
FeB |
56Fe(n,α)53Cr |
... |
0.395 (Fe) |
5.2–11.9 |
NiB |
58Ni(n,α)55Fe |
... |
5.58 (Ni) |
3.9–10.1 |
CuB |
63Cu(n,α)60Co |
... |
0.330 |
4.74–11.1 |
Helium Production Largely |
|
|
|
|
|
5.4 An application for the HAFM method lies in the direct analysis of pressure vessel wall scrapings or Charpy block surveillance samples. Measurements of the helium production in these materials can provide in situ integral information on the neutron fluence spectrum. This application can provide dosimetry information at critical positions where conventional dosimeter placement is difficult if not impossible. Analyses must first be conducted to determine the boron, lithium, and other component concentrations, and their homogeneities, so that their possible contributions to the total helium production can be determined. Boron (and lithium) can be determined by converting a fraction of the boron to helium with a known thermal neutron exposure. Measurements of the helium in the material before and after the exposure will enable a determination of the boron content (5.5 By careful selection of the appropriate HAFM sensor material and its mass, helium concentrations ranging from ∼10−14 to 10−1 atom fraction can be generated and measured. In terms of fluence, this represents a range of roughly 1012 to 1027 n/cm2. Fluence (>1 MeV) values that may be encountered during routine surveillance testing are expected to range from ∼3 × 1014 to 2 × 10 20 n/cm2, which is well within the range of the HAFM technique.
5.6 The analysis of HAFMs requires an absolute determination of the helium content. The analysis system specified in this test method incorporates a specialized mass spectrometer in conjunction with an accurately calibrated helium spiking system. Helium determination is by isotope dilution with subsequent isotope ratio measurement. The fact that the helium is stable makes the monitors permanent with the helium analysis able to be conducted at a later time, often without the inconvenience in handling caused by induced radioactivity. Such systems for analysis exist, and additional analysis facilities could be reproduced, should that be required. In this respect, therefore, the analytical requirements are similar to other ASTM test methods (compare with Test Method E244).
1.1 This test method describes the concept and use of helium accumulation for neutron fluence dosimetry for reactor vessel surveillance. Although this test method is directed toward applications in vessel surveillance, the concepts and techniques are equally applicable to the general field of neutron dosimetry. The various applications of this test method for reactor vessel surveillance are as follows:
1.1.1 Helium accumulation fluence monitor (HAFM) capsules,
1.1.2 Unencapsulated, or cadmium or gadolinium covered, radiometric monitors (RM) and HAFM wires for helium analysis,
1.1.3 Charpy test block samples for helium accumulation, and
1.1.4 Reactor vessel (RV) wall samples for helium accumulation.
1.2 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.
Standard Guide for Application of Neutron Transport Methods for Reactor Vessel Surveillance |
|
Standard Master Matrix for Light-Water Reactor Pressure Vessel Surveillance Standards |
|
Standard Guide for Sensor Set Design and Irradiation for Reactor Surveillance |
|
Standard Practice for Analysis and Interpretation of Light-Water Reactor Surveillance Neutron Exposure Results |
|
Standard Test Method for Application and Analysis of Solid State Track Recorder (SSTR) Monitors for Reactor Surveillance |
|
Standard Guide for Predicting Radiation-Induced Transition Temperature Shift in Reactor Vessel Materials |
|
Standard Test Method for Application and Analysis of Radiometric Monitors for Reactor Vessel Surveillance |
|
Standard Terminology Relating to Nuclear Materials |
|
Standard Guide for Application of Neutron Spectrum Adjustment Methods in Reactor Surveillance |
|
Standard Practice for Determining Neutron Fluence, Fluence Rate, and Spectra by Radioactivation Techniques |
|
Standard Guide for Application of ASTM Evaluated Cross Section Data File (Includes all amendments and changes 7/2/2020). |
|
Test Method for Atom Percent Fission in Uranium and Plutonium Fuel (Mass Spectrometric Method) (Withdrawn 2001) |
|
Standard Terminology Relating to Radiation Measurements and Dosimetry |
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