ML042260212
| ML042260212 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 07/14/2004 |
| From: | Los Alamos National Laboratory |
| To: | NRC/SECY/RAS |
| Byrdsong A T | |
| References | |
| 50-413-0LA, 50-414-OLA, ASLBP 03-815-03-OLA, Catawba-Intervenor-H, LA-UR-00-5079, RAS 8294 NUREG/CR-6744 | |
| Download: ML042260212 (20) | |
Text
ins SC2 94 DOCKETED USNRC August 9, 2004 (11:45AM)
OFFICE OF SECRETARY RULEMAKINGS AND ADJUDICATIONS STAFF EXHIBIT H NUCILR REGULTORY COMMISSION Docket 11. 0'0 -q 13/t Igg- ad 1 ZA. E In the mtEr d f
! ri.l -bs Staff_ IDENIfED /b lo Applicant __ RECEIVED Intervenor _ REJECTED Cont'g Off'r Contractor - . DATE Other _ Witness Reporter !C S6CYr- OX
'Tem ~plde =5* cVY-O049
I NUREG/CR-6744 LA-UR-00-5079 Phenomenon Identification and Ranking Tables (PIRTs) for Loss-of-Coolant Accidents in Pressurized and Boiling Water Reactors Containing High Burnup Fuel Los Alamos National Laboratory U.S. Nuclear Regulatory Commission Office of Nuclear Regulatory Research Washington, DC 20555-0001
Table D-1. PWR and BWR LOCA. Category D- Separate Effect Testing (continued)
Subcategory (Test type) I Phenomena (Parameter) I Definition and Rationale (Importance, Applicability, and Uncertainty)
Simulation of fuel Specimen selection: The amount of bumup to which the fuel rod used for the specimen was exposed.
relocation Burnup H(4) Fuel morphology (fragmentation, rim characteristics, bonding, etc.) is important. The nature of the bonding between the pellet and the cladding changes with the bumup increase. It will affect the potential for fuel relocation. The segment burnup level can determine the extent of pellet-cladding bonding and corresponding susceptibility to fuel relocation during ballooning and rupture. Fuel and rim-zone microstructure and the state of bonding with cladding are strongly influenced by fuel bumup.
M(O) No votes.
L(O) No votes.
Fuel: Y(1) MOX agglomerates Clad; N Reactor N Bumup: N Data PK(3).- Datajudgement UKC(O): No votes.
Appendix D-66
, f (continued)
Table D-1. PWR and BWR LOCA. Category D- Separate Effect Testing Subcategory (Test tvpe) I Phenomena (Parameter) I Definition and Rationale (Importance, Applicability, and Uncertainty)
Simulation of fuel Specimen selection: Composition of the fuel, iLe., a specified MOX compositiorL relocation Fuel type (MOX)
H(2) May affect the amount of fine grain material after relocation. Fuel structure and mechanical properties are Influenced by fuel type.
M(1) The consequence of fuel fragments relocation (higher local decay heat and higher cladding temperature) could be more effective with MOX fuel than with U02 fuel. Nevertheless the viscoplastic properties of the MOX should Impair the fuel fragments relocation at high burnup.
L(1) No significant differences ih pellet-cladding bonding behavior or pellet and cracking behavior are anticipated or have been observed with MOX fuel, therefore no significant differences in relocation behavior are anticipated.
Fuel: N Clad: N Reactor: N Bumup: N K(1): Data PK(2): Data, judgement UK(l): Judgement Appendix D-67
Table D-1 PWR and BWR LOCA. Category D- Separate Effect Testing (continued)
Subcategory (Test type) l Phenomena (Parameter) Definition and Rationale (importance, Applicability, and Uncertainty)
Simulation of fuel Specimen selection: Composition or designation of the metal utilized In fuel-rod fabrication relocation Alloy type H(2) May affect burst (beta favoring or alpha favoring additions). Ductile burst and brittle failure by thermal shock and post-quench forces are influenced strongly by cladding alloy type M(1) In general compositional differences have not been observed to significantly affect cladding burst behavior. However, if significant differences in burst behavior occurred, the relocation characteristics could be similarly significantly altered.
L(1) Data show no significant impact of alloy type on the balloon size that could influence the fuel fragments relocation.
Fuel: N Clad: N Reactor: N Burnup: N K(2): Data PK(I): Data. Judgement UK(1): Judgement Appendix D-68
EffectTesting (continued)
Table D-1. PWR and BWR LOCA. Category D- Separate 4, &plicabillty, and Uncertalnty)
Subcateo (Test tpe) I Phenomena (Parameter) I Definition and Rationale (Importanee, the cladding prior to the Specimen selection: Chemical and mechanical bonding between the fuel pellet and Simulation of fuel test.
relocation Chemical and mechanlcal bonding potential for fuel 11(4) Fuel morphology (bondin) is important. It will affect the could significantly fragmentation relocation. It is speculated that bonding movement.
affect the relocation characteristics by Impeding pellet fragment that Influences However, this effect has not been demonstrated. Major factor and subsequent fuel slumping and potential release of fuel particles upon burst fragmentation.
M(O) No votes.
L(O) No votes.
Fuel: N Clad: N Reactor: N Burnup: N No votes.
PK(3): Data, Judgement UIC(l): Lack of data Appendix D-69
Separate Effect Testing (continued)
Table D1. FWR and BWR LOCA. Category D-(Importance, Applicability and Uncertainty)
Subcate (Test type) l Phenomena (Parameter) I Definition and Rationale the test.
Specimen selection: Crack pattern and crack density of the fuel pellets prior to Simulation of fuel relocation Cracking Degree of fuel cracking H(2) Controls the rubble bed characteristics after relocation. release.
directly influences the potential for fuel relocation and M(D) No votes. general the macroscopic L(2) Beyond a given burnup the number of cracks Isstable. In not change fuel pellet cracking pattern develops early in life and does with elevated exposures. Therefore, this contribution to fuel significantly parameter during this relocation susceptibility is not expected to be a dominant test series.
Fuel: N Clad: N Reactor: N Burnup, N K(l): Data PK(3): Data, Judgement UX(O): No votes.
d a
Appendix L)70
Table D-1. PWR and BWR LOCA. Category D- Separate Effect Testing (continued)
Subcategory Crest type) I Phenomena (Parameter) I Definition and Rationale (Importance, Applicability, and Uncertainty)
Simulation of fuel Conduct of Test-During Determination of whether blowdown processes must be simulated in the test.
relocation With or without blowdown H(0) No votes.
M(l) During the blowdown phase of the LOCA transient, fuel stored energy is redistributed in the pellet and the clad. This redistribution produces a decrease of the pellet centerline tenperature and increases the pellet rim and clad temperatures. Due to these temperature transients, the central part of the pellet will suffer a contraction while the rim and the clad will experience an expansion. These adverse effects could induce fuel mechanical stresses and fragmentation. The expansion and contraction inside the fuel pellet may affect bonding and fuel debris sizes.
L(2) Vibration loads occurring during the blowdown phase may cause additional pellet fragment movement. In general, pellet fragments are relatively constrained within the fuel rod by the column geometry, as evidenced by characterization of fuel column geometry in hot cells. Therefore, this effect is not considered to significantly contribute to relocation susceptibility later during the cladding heatup and rupture phases. Fuel thermal contraction and cladding heatup during the blowdown phase increases the pellet-cladding gap and possibly facilitates pellet fragment relocation. Cladding heatup rate and temperature, either with or without a blowdown, are the primary factors that influence burst shape and dimensional changes.
Fuel: N Clad: N Reactor: N Burnup: N No votes.
PK(1):
Data, Experience, Judgement UK(2): Judgement Appendix D-71
Table D-1. PWR and BWR LOCA. Category D- Separate Effect Testing (continued)
Subcategoq (est type) I Phenomnena (Parameter) I Deflnition and Rationale Importance, Applicability, and Uncertalnty)
Simulation of fuel Conduct of Test-During Simulation of the temperature response of the fuel and dadding during the blowdown relocation Blowdown temperature phase of a large-break LoCA.
transients for fuel and cladding H(2) Inportant parameters that influence dadding burst and dimensional changes.
M(O) No votes.
L(l) Pellet fragment movement. In general, pellet fragments are relatively constrained within the fuel rod by the column geometry, as evidenced by characterization of fuel column geometry In hot cells. Therefore, this effect is not considered to significantly contribute to relocation susceptibility later during the cladding heatup and rupture phases. Fuel thermal contraction and cladding heatup during the blowdown phase Increases the pellet-cladding gap and possibly facilitates pellet fragment relocation. Cadding heatup rate and temperature, either with or without a blowdown, are the primary factors that influence burst shape and dimensional changes.
Fuel: N
[Clad: N Reactor: N Burnup: N K(1): Data, Judgement PK(2): Data, Experience, Judgement UK(O): No votes.
Appendix D-72
Table D1. PWR and BWR LOCA. Category D- Separate Effect Testing (continued)
Subcategory (Test type) l Phenomena (Parameter) I Definition and Rationale (Importance, Applicability, and Uncertainty)
Simulation of fuel Conduct of Test-During Look at the impact of fuel fragment relocation on the cladding temperature during the relocation Pie- and post-burst test high temperature oxidation phase and the quenching phase.
phases (2)
H(1) pata of fuel relocation determines the Impacted phases.
M(3) Needs inpile test to be prototypical (heating source should come from the fuel). If the objective Is as speculated above, this test would help to characterize at which point In time the bulk of the relocation occurs.
However, most rods that balloon also burst and It is not clear that a separation In time would significantly affect the LOCA performance (Le., whether relocation occurs Instantaneously to fill the ballooned region as opposed to instantaneous relocation on burst). Burst shape and dimensional changes are influenced by clad phase at the time of ballooning and burst.
L(O) No votes.
Fuel: N Clad: N Reactor. N Bumnup: N K(1): Data Judgement PK(3): Data, Calculation, Judgement UK(O): No votes.
Appendix D-73
Table D-1. FWR and BWR LOCA. Category D- Separate Effect Testing (continued)
Subcategory (Test type) I Phenomena (Parameter) I Definition and Rationale Importance, Applicability, and Uncertainty)
Simulation of fuel Conduct of Test-During The amount of gas In the rod upper plenum, for a given initial pressure in the test rod.
relocation Internal pressure and moles of gas H(3) Driving force for relocation, together with gravity. It Is crucial to have a pressure evolution representative of a full-length rod. Internal gas pressure is I
the driving force for fuel fragments relocation. To be prototypical the amount of gas withn the rod prior to the test has to be maintained constant. The internal pressure isa'measured parameter, not an Input data. Initial pressure is the primary factor that determines the burst temperature and shape and potential release of fuel particles from rim zone at burst. Plenum gas inventory is a secondary factor.
M(1) If gas flow is the primary relocation mechanism, then an accurate simulation of that gas flow would be needed to obtain the most meaningful results. However, It Is anticipated that similar relocation behavior would be obtained over a relatively wide range of gas flows.
L(O) No votes.
Fuel: N Clad: N Reactor N Bumup- N K(O): No votes.
PK(4): Data, Calculations, Judgement UK(O): No votes.
Appendix D-74
Table D-1. PWR and BWR LOCA. Category D- Separate Effect Testing (continued)
Subcateory rest type) I Phenomena (Parameter) I Deflnition and Rationale (Mportance, Applicability, and Uncertainty)
Simulation of fuel Conduct of Test-During During ballooning and after burst, the fuel rod vibration induced by the flow can favour relocation Flow induced vibration crumbling of the fuel pellet stack.
H(O) No votes.
M(2) Fuel column axial gaps have been observed to form and continue during normal reactor operation. This results suggests that fuel column shakeout is not likely with normal flow-induced vibration even over very extended periods. It is further noted that with cladding perforation, steam ingress will promote fuel pellet oxidation that has been observed, with failed fuel during normal reactor operation, to cause effective blockage within the fuel rod to preclude fuel downward fuel pellet fragment motion, again overriding the effects of flow induced vibration. Secondary driving force.
L(2) Potential impact of rod vibration is expected to be small. Ballooning and burst occur after blowdown, and steam-flow-induced vibration during and after blowdown would be insignificant.
Fuel: N Clad: N Reactor N Burnup: N K(O): No votes.
PK(2): Data, Judgement UK(I): Judgement Appendix D-75
Table D-1. FWM and BWIR LOCA. Category D- Separate Effect Testing (continued)
Subcategoty (Test type) Phenomena M (Parameter) l efinition and Rationale Ym t licabIlt, and Uncertain Simulation of fuel Conduct of Test-During Manner In which test specimen Isconstrained by surrounding rods to simulate potenail relocation Exterior rod constraints in-reactor behavior.
H(I) Prior ballooning experiments have shown that coplanar ballooning is not likely, and therefore balloons may not be constrained by adjacent ballooned sections. However, the constraints provided by adjacent non-ballooned rods orl still provide a significant restriction on the amount of cladding ballooning ami corresponding fuel relocation.
M(1) Rod constraints during ballooning may affect the fuel distribution at the relocation site.
L(2) The purpose of these tests is to analyze the separate effect of fuel fragment relocation. Exterior constraints influence ballooning shape to some extent.
Fuel: Y(1). Most modern BWR fuel designs use part-length fuel rods resulting in zones where there is a significant gap between adjacent rods (because rods in certain lattice locations terminate at a lower elevation). This design feature may permit greater ballooning and relocation at those elevations. However, the fuel rods at those peculiar bocations would correspondinly experience a circumferential temperature gradient, which is known to reduce the resulting burst strain.
Clad: N Reactor: N Burmup: N K(O): No votes.
PK(4): Data, Judgement UK(O): No votes.
Appendix D>76 i
Table D-1. PWR and DWR LOCA. Category D- Separate Effect Testing (continued)
Subcategory ETest type) I Phenomnena (Parameter) I Definition and Rationale (Importance, Applicability, and Uncertainty)
Simulation of fuel Conduct of Test-During Determination of the dimensions of the ballooned area and the cladding breach during relocation Balloon size and burst the test.
size H(4) Affects the amount of relocated fuel in the balloon. The balloon and burst size represents the maximum potential volume for relocation. Directly influence the potential for fuel relocation, slumping, and release at ands after burst.
M(O) No votes.
L(1) Balloon size and burst size are measured after the test. No need to measure it on-line Fuel: N Clad: N Reactor. N Burnup: N K(l): Judgement PK(2): Data, Judgement UK(O): No votes.
Appendix D-77
Effect Testing (continued)
Table D-1. PWR and BWR LOCA. Category D- Separate Uncertainty) l Phenomena (Parameter) l Definition and Rationale (mportance Applicability, and Subcategory (Test type)
Conduct of Test-Durng Longitudinal dimension of the fuel rod segment to be tested.
Simulation of fuel relocation Length gas pressure In H(2) The driving force for fuel fragments relocation Is the inteknal is significantly the plenum. For high burnup fuel rods the axial gas transport The rod Impaired. A short rod would favor the plenum gas partidpation At the least, the length has to be prototypical to avoid experimental bias.
length between two grids must be tested.
the potential fuel M(1) The amount of fuel above the ballooned/burst section defines region volume to be relocated. However, the size of the ballooned/burst if the defines the maximum possible relocated fuel volume. Therefore, certainty, sufficient ballooned/burst location can be defined with reasonable relocation.
length can be provided above that region to enable prototypic inches) is sufficient.
L(l) Length more than about'15 times of the pellet length (6 Fuel:
Clad:
Bumup N K(l):
N N
Reactor. N Calculation I
I PK(3): Data, Judgemnent UK(O): No votes.
Appendix 0-78 I
Table D-1. PWR and BWR LOCA. Category D- Separate Effect Testing (continued)
Subcategory (Test type) I Phenomena (Parameter) I Definition and Rationale Umporance, Applicability, and Uncertainty)
Simulation of fuel Conduct of Test-PTE Granularity of dispersed fuel fragments is measured to get relevant information on the relocation Granularity of dispersed fuel density In the relocated fuel fragments zone.
material H(3) The equivalent fuel density of the relocated fragments allows codes to simulate the local overheating of the dadding. Major factor that influences the potential for fuel relocation and release.
M(l) Smaller pellet fragments would be expected to result in easier fuel movement and possibly a higher density of relocated fuel. However, pellet cracking patterns are established early in life and do not vary greatly with increased exposure, so a widely varied granularity of material, prior to dispersal, is not expected.
LO) No votes.
Fuel: N Clad: N Reactor. N Burnup: N K(O): No votes.
PK(4): Data, Judgement UK(O): No votes.
Appendix D-79
Table D-1. PWR and BWR LOCA. Category D- Separate Effect Testing (continued)
Subcategory (Test type) Phenomena (Parameter) I Definition and RatlonaL (Importance, Applicability, and Uncertainty)
P Simulation of fuel Conduct of Test-PIE Non-intrusive measurement of the temperature differences of the tested fuel rod.
relocation Thermography H(1) Provides the fuel distribution In 3D.
M(O) No votes.
L(2) Low added value Fuel: N Clad: N Reactor: N Burnup: N K(O): Data PK(2): Data, Judgement
.UK(1): Judgement Appendix D-8O
Table D-1. PWR and BWR LOCA. Category D- Separate Effect Testing (continued)
Subeategorytrestype) l Phenomena(Parameter) I DefinitionandRationale(Importance ApplicabilityandUnertinty)
Simulation of fuel Conduct of Test-PTH Self defined.
relocation Thermal diffusivity of rubble bed H(l) Output parameter.
M(l) Probably difficult to do, but would be useful in quantifying the effective thermal properties of the rubble mass Chis assumes that in the ballooned/burst region U the material Is still there - it may be worthwhile to capture this just prior to burst although there may not be significant relocation at that time if gas flow is the primary relocation mechanism), otherwise this is best done analytically.
L(l) No rationale provided.
Fuel: N Clad: N Reactor: N Bumup: N IC(O): No votes.
PK(2): Data, Judgement UIC(1): Judgement Appendix D-81
Table D-1. PWMand BWR LOCA. Category D- Separate Effect Testing (continued)
Subcategory (Test type} I Phenomena (Parameter) I Definition and Rationale (importance, AppIicabili!L, and Uncertainty)
Simulation of fuel Conduct of Test-PIE Measure the shape and the size of the ballooned area of the tested fuel rod.
relocation Strain profile of cladding as f(G z) H(3) The purpose of this test is to assess the amount and characteristics of relocation. A determining aspect of that process Is the amount of ballooning (free volume to which the fuel may relocate), and therefore this volume should be known In any assessment of relocation characteristics. Note that the circumferential variation of cladding strain should also be determined. Axial variation of clad circumferential strain is a parameter that directly influences the potential for fuel relocation and slumping.
M(1) Will give some indications on potential Impact of the balloon the shape (magnitude and extension) on the amount of relocated fuel.
L(O) No iNotes.
FueL N Clad: N Reactor: N Burnup- N K(l): Judgement, Cakulation PK(3): Data, Judgement UK(O): No votes.
I Appendix D-82 I
Table Dot. PWR and BWR LOCA Category D- Separate Effect Testing (continued)
Subcategory (Test type) I Phenomena (Parameter) l Definition and Rationale (IUportance, Applicability, and Uncertainty)
Simulation of fuel Conduct of Test-PIE Determination of the mass of fuel remaining within the tested fuel rod and the mass that relocation Material balance (In-rod left the fuel rod through the rupture.
and dispersed)
H(2) This is the primary result to be quantified In this test series, to be correlated with the ballooned region and burst size. It is the amount of lost material that is of Interest as It could possibly contribute to such effects as flow blockage, etc.
M(O)
L(2) This information is covered by the local measurement of the fuel density.
Fuel: N Clad: N Reactor: N Burnup: N K(1): Judgement PK(2): Data, Judgement UK(1): Judgement Appendix D-84 i