{"id":24475,"date":"2024-10-17T00:11:54","date_gmt":"2024-10-17T00:11:54","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/astm-e705-2008-2\/"},"modified":"2024-10-24T13:32:28","modified_gmt":"2024-10-24T13:32:28","slug":"astm-e705-2008-2","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/astm\/astm-e705-2008-2\/","title":{"rendered":"ASTM-E705 2008"},"content":{"rendered":"
\n Significance and Use <\/b><\/p>\n

Refer to Practice E 261 for a general discussion of the determination of fast-neutron fluence rate with fission detectors.<\/p>\n

237 <\/sup> Np is available as metal foil, wire, or oxide powder. For further information, see Guide E 844. It is usually encapsulated in a suitable container to prevent loss of, and contamination by, the 237 <\/sup> Np and its fission products.<\/p>\n

One or more fission products can be assayed. Pertinent data for relevant fission products are given in Table 1 and Table 2.<\/p>\n

137 <\/sup> Cs- 137m <\/sup> Ba is chosen frequently for long irradiations. Radioactive products 134 <\/sup> Cs and 136 <\/sup> Cs may be present, which can interfere with the counting of the 0.662 MeV 137 <\/sup> Cs- 137m <\/sup> Ba gamma ray (see Test Methods E 320).<\/p>\n

140 <\/sup> Ba- 140 <\/sup> La is chosen frequently for short irradiations (see Test Method E 393).<\/p>\n

95 <\/sup> Zr can be counted directly, following chemical separation, or with its daughter 95 <\/sup> Nb, using a high-resolution gamma detector system.<\/p>\n

144 <\/sup> Ce is a high-yield fission product applicable to 2- to 3-year irradiations.<\/p>\n

It is necessary to surround the 237 <\/sup> Np monitor with a thermal neutron absorber to minimize fission product production from trace quantities of fissionable nuclides in the 237 <\/sup> Np target and from 238 <\/sup> Np and 238 <\/sup> Pu from (n, \u03b3 <\/span> ) reactions in the 237 <\/sup> Np material. Assay of 238 <\/sup> Pu and 239 <\/sup> Pu concentration is recommended when a significant contribution is expected.<\/p>\n

Fission product production in a light-water reactor by neutron activation products 238 <\/sup> Np and 238 <\/sup> Pu has been calculated to be insignificant (1.2 %), compared to that from 237 <\/sup> Np(n,f), for an irradiation period of 12 years at a fast neutron ( E <\/span> > 1 MeV) fluence rate of 1 \u00d7 <\/span> 10 11 <\/sup> cm \u2212 <\/span> 2 <\/sup> \u00b7 <\/span> s \u2212 <\/span> 1 <\/sup> , provided the 237 <\/sup> Np is shielded from thermal neutrons (see Fig. 2 of Guide E 844).<\/p>\n

Fission product production from photonuclear reactions, that is, ( \u03b3 <\/span> ,f) reactions, while negligible near-power and researchreactor cores, can be large for deep-water penetrations (1). <\/span><\/p>\n

Good agreement between neutron fluence measured by 237 <\/sup> Np fission and the 54 <\/sup> Fe(n,p) 54 <\/sup> Mn reaction has been demonstrated (2). <\/span> The reaction 237 <\/sup> Np(n,f) F.P. is useful since it is responsive to a broader range of neutron energies than most threshold detectors.<\/p>\n

The 237 <\/sup> Np fission neutron spectrum-averaged cross section in several benchmark neutron fields are given in Table 3 of Practice E 261. Sources for the latest recommended cross sections are given in Guide E 1018. In the case of the 237 <\/sup> Np(n,f)F.P. reaction, the recommended cross section source is the ENDF\/B-VI cross section (MAT = 9346) revision 1 (3) <\/span> . Fig. 1 shows a plot of the recommended cross section versus neutron energy for the fast-neutron reaction 237 <\/sup> Np(n,f)F.P.<\/p>\n

Note <\/span> 1\u2014The data are taken from the Evaluated Nuclear Data file, ENDF\/B-VI, rather than the later ENDF\/B-VII. This is in accordance with Guide E 1018 Guide for Application of ASTM Evaluated Cross Section Data File, 6.1. since the later ENDF\/B-VII data files do not include covariance information. For more details see Section H of (10) <\/span><\/p>\n

TABLE 1 Recommended Nuclear Parameters for Certain Fission Products<\/p>\n

A <\/span> <\/sup> The lightface numbers in parentheses are the magnitude of plus or minus uncertainties in the last digit(s) listed.<\/p>\n

B <\/span> <\/sup> With 137m <\/sup> Ba (2.552 min) in equilibrium.<\/p>\n

C <\/span> <\/sup> Probability of daughter 140 <\/sup> La decay.<\/p>\n

D <\/span> <\/sup> With 140 <\/sup> La (1.6781 d) in transient equilibrium.<\/p>\n

TABLE 2 Recommended Fission Yields for Certain Fission Products A <\/span> <\/sup><\/p>\n

A <\/span> <\/sup> Special issue on Evaluated Nuclear Data File ENDF\/B-VII.0. \u201d <\/span> Nuclear Data Sheets, J.K. Tull Editor. Vol. 107 December 2006. Data available on the ENDF\/B-VII website at URL:http:\/\/www.nndc.bnl.gov\/exfor\/endf00.htm.<\/p>\n

B <\/span> <\/sup> All yield data given as a %; RC represents a cumulative yield; RI represents an independent yield.<\/p>\n

FIG. 1 ENDF\/B-VI Cross Section Versus Energy for the 237 <\/sup> Np(n,f)F.P. Reaction <\/span><\/p>\n

1. Scope <\/b><\/p>\n

1.1 This test method covers procedures for measuring reaction rates by assaying a fission product (F.P.) from the fission reaction 237 <\/sup> Np(n,f)F.P.<\/p>\n

1.2 The reaction is useful for measuring neutrons with energies from approximately 0.7 to 6 MeV and for irradiation times up to 30 to 40 years.<\/p>\n

1.3 Equivalent fission neutron fluence rates as defined in Practice E 261 can be determined.<\/p>\n

1.4 Detailed procedures for other fast-neutron detectors are referenced in Practice E 261.<\/p>\n

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.<\/p>\n

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. <\/span><\/p>\n

2. Referenced Documents <\/b> (purchase separately) <\/i> The documents listed below are referenced within the subject standard but are not provided as part of the standard.<\/span><\/p>\n

ASTM Standards <\/b><\/p>\n

E170<\/span> Terminology Relating to Radiation Measurements and Dosimetry E181<\/span> Test Methods for Detector Calibration and Analysis of Radionuclides E261<\/span> Practice for Determining Neutron Fluence, Fluence Rate, and Spectra by Radioactivation Techniques E262<\/span> Test Method for Determining Thermal Neutron Reaction Rates and Thermal Neutron Fluence Rates by Radioactivation Techniques E320<\/span> Test Method for Cesium-137 in Nuclear Fuel Solutions by Radiochemical Analysis E393<\/span> Test Method for Measuring Reaction Rates by Analysis of Barium-140 From Fission Dosimeters E704<\/span> Test Method for Measuring Reaction Rates by Radioactivation of Uranium-238 E844<\/span> Guide for Sensor Set Design and Irradiation for Reactor Surveillance, E 706 (IIC) E944<\/span> Guide for Application of Neutron Spectrum Adjustment Methods in Reactor Surveillance, E 706 (IIA) E1005<\/span> Test Method for Application and Analysis of Radiometric Monitors for Reactor Vessel Surveillance, E 706 (IIIA) E1018<\/span> Guide for Application of ASTM Evaluated Cross Section Data File, Matrix E706 (IIB) <\/p>\n

Keywords <\/b><\/p>\n

fission dosimeter; fission produc<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

E705-08 Standard Test Method for Measuring Reaction Rates by Radioactivation of Neptunium-237 (Redline)<\/b><\/p>\n\n\n\n\n
Published By<\/td>\nPublication Date<\/td>\nNumber of Pages<\/td>\n<\/tr>\n
ASTM<\/b><\/a><\/td>\n2008<\/td>\n6<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":24476,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2637],"product_tag":[],"class_list":{"0":"post-24475","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-astm","8":"first","9":"instock","10":"sold-individually","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/24475","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/24476"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=24475"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=24475"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=24475"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}