1、Designation: C1553 16Standard Guide forDrying Behavior of Spent Nuclear Fuel1This standard is issued under the fixed designation C1553; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenthe
2、ses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide discusses three steps in preparing spentnuclear fuel (SNF) for placement in a sealed dry storagesystem: (1) evaluating the needs for drying th
3、e SNF afterremoval from a water storage pool and prior to placement indry storage, (2) drying the SNF, and (3) demonstrating thatadequate dryness has been achieved.1.1.1 The guide addresses drying methods and their limita-tions when applied to the drying of SNF that has been stored inwater pools. Th
4、e guide discusses sources and forms of waterthat may remain in the SNF, the container, or both after thedrying process has been completed. It also discusses theimportant and potential effects of the drying process and anyresidual water on fuel integrity and container materials duringthe dry storage
5、period. The effects of residual water arediscussed mechanistically as a function of the container ther-mal and radiological environment to provide guidance onsituations that may require extraordinary drying methods,specialized handling, or other treatments.1.1.2 The basic issues in drying are: (1) t
6、o determine howdry the SNF must be in order to prevent problems with fuelretrievability, container pressurization, or container corrosionduring storage, handling, and transfer, and (2) to demonstratethat adequate dryness has been achieved. Achieving adequatedryness may be straightforward for undamag
7、ed commercialfuel but complex for any SNF where cladding damage hasoccurred prior to or during placement and storage at the spentfuel pools. Challenges in achieving adequate dryness may alsoresult from the presence of sludge, CRUD, and any otherhydrated compounds. These may be transferred with the S
8、NFto the storage container and may hold water and resist drying.1.1.3 Units are given in both SI and non-SI units as isindustry standard. In some cases, mathematical equivalents aregiven in parentheses.1.2 This standard only discusses SNF drying and does notpurport to address all of the handling and
9、 safety concerns, ifany, associated with the drying process(es). It is the responsi-bility of the user of this standard to establish appropriate safetyand health practices and to meet regulatory requirements priorto and during use of the standard.2. Referenced Documents2.1 ASTM Standards:2C859 Termi
10、nology Relating to Nuclear MaterialsC1174 Practice for Prediction of the Long-Term Behavior ofMaterials, Including Waste Forms, Used in EngineeredBarrier Systems (EBS) for Geological Disposal of High-Level Radioactive WasteC1562 Guide for Evaluation of Materials Used in ExtendedService of Interim Sp
11、ent Nuclear Fuel Dry Storage Sys-tems2.2 ANSI/ANS Standards:3ANSI/ANS 8.1-1998 Nuclear Criticality Safety in Opera-tions with Fissionable Materials Outside ReactorsANSI/ANS-8.7-1998 Nuclear Criticality Safety in the Stor-age of Fissile MaterialsANSI/ANS-57.9 American National Standard Design Crite-r
12、ia for Independent Spent Fuel Storage Installation (DryType)2.3 Government Documents:4The U.S. government docu-ments listed in 2.3 or referenced in this standard guide areincluded as examples of local regulations and regulatoryguidance that, depending on the location of the dry storage site,may be a
13、pplicable. Users of this standard should adhere to theapplicable regulatory documents and regulations and shouldconsider applicable regulatory guidance.Title 10 on Energy, Code of Federal Regulations, Part 60, 10CFR 60, U.S. Code of Federal Regulations, Disposal ofHigh Level radioactive Wastes in Ge
14、ologic RepositoriesTitle 10 on Energy, Code of Federal Regulations, Part 63, 10CFR 63, U.S. Code of Federal Regulations, Disposal of1This guide is under the jurisdiction of ASTM Committee C26 on Nuclear FuelCycle and is the direct responsibility of Subcommittee C26.13 on Spent Fuel andHigh Level Was
15、te.Current edition approved July 1, 2016. Published November 2016. Originallyapproved in 2008. Last previous edition approved in 2008 as C1553 08. DOI:10.1520/C1553-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual
16、 Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.4The Code of Federal Regulations is available at https:/www.gpo.go
17、v/fdsys/browse/collectionCfr.action?collectionCode=CFR. SFST-ISG-1 is available athttp:/www.nrc.gov/reading-rm/doc-collections/isg/spent-fuel.html.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1High-Level Radioactive Wastes in Geolog
18、ic Repository atYucca Mountain, NevadaTitle 10 on Energy, Code of Federal Regulations, Part 71, 10CFR 71, U.S. Code of Federal Regulations, Packaging andTransport of Radioactive MaterialsTitle 10 on Energy, Code of Federal Regulations, Part 72, 10CFR 72, U.S. Code of Federal Regulations, LicensingRe
19、quirements for the Independent Storage of SpentNuclear Fuel and High-Level Radioactive WasteTitle 10 on Energy, Code of Federal Regulations, Part 961,10 CFR 961 U.S. Code of Federal Regulations, StandardContract for Disposal of Spent Nuclear Fuel and/orHigh-Level Radioactive Waste SFST-IST-1, Damage
20、dFuel3. Terminology3.1 DefinitionsFor definitions of terms used in this guidebut not defined herein, refer to Terminology C859 or PracticeC1174.3.2 Definitions of Terms Specific to This Standard: Refer toSFST-ISG-1 for additional definition details.3.2.1 breached spent fuel rod, or failed fuel, nspe
21、nt fuelrod with cladding defects that permit the release of gas fromthe interior of the fuel rod. A breached spent fuel rod may alsohave cladding defects sufficiently large to permit the release offuel particulate. A breach may be limited to a pinhole leak orhairline crack, or may be a gross breach.
22、3.2.2 CRUD, nin nuclear waste management, deposits onfuel surfaces from corrosion products that circulate in thereactor coolant. Compositions of the deposits reflect materialsexposed to coolant and activation products formed duringirradiation. Term was originally an acronym for “Chalk RiverUnidentif
23、ied Deposits.”3.2.3 damaged SNF, nin nuclear waste management, anyfuel rod of fuel assembly that cannot fulfill its fuel-specific orsystem-related functions.3.2.4 disposal, nin nuclear waste management, the em-placement of radioactive materials and wastes in a geologicrepository with the intent of l
24、eaving them there permanently.3.2.5 getter, nin nuclear waste management, a material(typically a solid) used to chemically react with certain gases(for example, H2,O2,H2O vapor) to form a solid compound oflow vapor pressure.3.2.5.1 DiscussionSome fuel rod designs include an inter-nal getter to remov
25、e residual hydrogen/moisture from theinternal rod atmosphere.3.2.6 grossly breached spent fuel rod, na subset ofbreached rods. A breach in spent fuel cladding that is largerthan a pinhole leak or a hairline crack and that may permit fuelparticulate release.3.2.7 independent spent fuel storage instal
26、lation (ISFSI),na system designed and constructed for the interim storage ofspent nuclear fuel and other radioactive materials associatedwith spent fuel storage.3.2.8 intact SNF, nany fuel that can fulfill all fuel-specificand system-related functions, and that is not breached. Notethat all intact S
27、NF is undamaged, but not all undamaged SNFis intact, since in most situations, breached spent fuel rods thatare not grossly breached will be considered undamaged.3.2.9 packaging, or SNF storage container, nin nuclearwaste management, an assembly of components used to ensurecompliance with the applic
28、able requirements for independentstorage of spent nuclear fuel and high-level radioactive wasteor for transportation of radioactive materials.3.2.10 pinhole leaks or hairline cracks, nminor claddingdefects that will not permit significant release of particulatematter from the spent fuel rod, and the
29、refore present a minimalconcern during fuel handling and retrieval operations. (Seediscussion of gross defects for size concerns.)3.2.11 repository, geologic repository, n in nuclear wastemanagement, a disposal site, a permanent location for radio-active wastes.3.2.12 spent nuclear fuel (SNF), nnucl
30、ear fuel that hasbeen irradiated in a nuclear reactor and contains fissionproducts, activation products, actinides, and unreacted fission-able fuel.3.2.13 sludge, nin nuclear waste management, a slurry orsediment containing nuclear waste materials; a residue, gener-ally radioactive, that has usually
31、 been formed from processingoperations, corrosion, or other similar reactions.3.2.14 undamaged SNF, nSNF that can meet all fuel-specific and system-related functions. Undamaged fuel may bebreached. Fuel assemblies classified as undamaged SNF mayhave assembly defects.3.2.15 waste package, nin nuclear
32、 waste management,the waste form and any containers, shielding, packing, andother materials immediately surrounding an individual wastecontainer.3.2.16 water, nin drying of spent nuclear fuel, refers to thevarious forms of H2O present in the fuel storage container. It isthe total amount of moisture
33、(specified by weight, volume, ornumber of moles) present in a container as a combination ofvapor, free or unbound liquid H2O, physisorbed H2O,chemisorbed H2O, and ice. The following specific terms forwater are used in this document:3.2.16.1 bound water, nadsorbed surface layers of waterand chemisorb
34、ed water.3.2.16.2 chemisorbed water, nwater that is bound to otherspecies by forces whose energy levels approximate those of achemical bond.3.2.16.3 physisorbed water (adsorbed water), n water thatis physically bound (as an adsorbate, by weak forces) tointernal or external surfaces of solid material
35、.3.2.16.4 trapped water, nunbound water that is physicallytrapped or contained by surrounding matrix, blocked ventpores, cavities, or by the nearby formations of solids thatprevent or slow the escape of water from the waste package.3.2.16.5 unbound/free water, nwater, in the solid, liquid,or vapor s
36、tate, that is not physically or chemically bound toanother species.C1553 1624. Significance and Use4.1 Drying of the SNF and fuel cavity of the SNF containerand its internals is needed to prepare for sealed dry storage,transportation, or permanent disposal at a repository. Thisguide provides technic
37、al information for use in determining theforms of water that need to be considered when choosing adrying process. This guide provides information to aid in (a)selecting a drying system, (b) selecting a drying method, and(c) demonstrating that adequate dryness was achieved.4.2 The considerations affe
38、cting drying processes include:4.2.1 Water remaining on and in commercial, research, andproduction reactor spent nuclear fuels after removal from wetstorage may become an issue when the fuel is sealed in a drystorage system or transport cask. The movement to a drystorage environment typically result
39、s in an increase in fueltemperature, which may be sufficient to cause the release ofwater from the fuel. The water release coupled with thetemperature increase in a sealed container may result incontainer pressurization, corrosion of fuel or assemblystructures, or both, that could affect retrieval o
40、f the fuel, andcontainer corrosion.4.2.2 Removal of the water associated with the SNF may beaccomplished by a variety of technologies including heating,imposing a vacuum over the system, flushing the system withdry gases, and combinations of these and other similar pro-cesses.4.2.3 Water removal pro
41、cesses are time, temperature, andpressure-dependent. Residual water in some form(s) should beanticipated.4.2.4 Drying processes may not readily remove the waterthat was retained in porous materials, capillaries, sludge,CRUD, and as thin wetted surface films. Water trapped withindamaged SNF may be es
42、pecially difficult to remove.4.2.5 Drying processes may be even less successful inremoving bound water from the SNF and associated materialsbecause removal of bound water will only occur when thethreshold energy required to break the specific water-materialbonds is applied to the system. For spent n
43、uclear fuel thisthreshold energy may come from the combination of thermalinput from decay heat and forced gas flow and from theionizing radiation itself.4.2.6 The adequacy of a drying procedure may be evaluatedby measuring the response of the system after the dryingoperation is completed. For exampl
44、e, if a vacuum dryingtechnology is used for water removal, a specific vacuum couldbe applied to the system, the vacuum pumps turned off, and thetime dependence of pressure rebound measured. The reboundresponse could then be associated with the residual water,especially unbound water, in the system.4
45、.2.7 Residual water associated with the SNF, CRUD, andsludge inside a sealed package may become available to reactwith the internal environment, the fuel, and the packagematerials under dry storage conditions.4.2.8 Thermal gradients within the container evolve withtime, and as a result water vapor w
46、ill tend to migrate to thecooler portions of the package. Water may condense in theseareas. Condensed water will tend to migrate to the physicallylower positions under gravity such as the container bottom.4.2.9 Radiolytic decomposition of hydrated and other water-containing compounds may release moi
47、sture, oxygen andhydrogen to the container.4.2.10 Extended time at temperature, coupled with thepresence of ionizing radiation, may provide the energy neces-sary to release bound or trapped water to the container.5. Evaluating the Drying Approach5.1 The proper approach to drying SNF is fuel and syst
48、em-specific, and thus will depend on fuel type, fuel condition, fuelbasket design, and associated materials (such as the neutronabsorber in the basket). There is no single correct or evenpreferred approach. Intact commercial fuel may be dried byone approach, SNF with breached fuel rods by anotherapp
49、roach, and research and production reactor fuels by yetanother approach. Furthermore, the variables that must beconsidered in selecting a drying approach for one fuel type maydiffer significantly from those that are important for anotherfuel type. For example, hydrogen/hydride behavior should beconsidered in fuel systems clad with zirconium-based alloysbut is not important to aluminum or stainless steel clad SNF.The proper drying approach will minimize the potential fordamage of the fuel during the drying operation and subsequentdry storage. Reference (1) p
