ML042260219
| ML042260219 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 05/25/2004 |
| From: | Grandjean C, Hache G Institut De Protection Et De Surete Nucleaire (IPSN) |
| To: | NRC/SECY/RAS |
| Byrdsong A T | |
| References | |
| 50-413-0LA, 50-414-OLA, ASLBP 03-815-03-OLA, Catawba-Intervenor-L, RAS 8298 | |
| Download: ML042260219 (25) | |
Text
$V --- W DOCKETED USNRC August 9, 2004 (11:45AM)
OFFICE OF SECRETARY RULEMAKINGS AND ADJUDICATIONS STAFF EXHIBIT L NUCLEAR REGULATORY COMMISSION Docket No. 3 11 -CL Officalxh. o.
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LOCA Issues Related to Ballooning, Fuel relocation, Flow Blockage and Coolability Main Findings from a Review of Past Experimental Programs Claude GRANDJEAN, GeorgesHACHE IRSN, CE Cadarache, France SEGFSM Topical Meeting on LOCA Issues ANL, May 25-27, 2004 INSTITUT DE RADIOPROTECTION ET DE SORETE NUCLEAIRE IP
ME1, I, IRSN State-of-the Art Review on LOCA The S.o.A. review has been divided in 3 parts:
E 1st Part: Clad Ballooning and Rupture. Flow Blockage. Fuel relocation.
0 2nd Part: Coolability of Partially Blocked Regions in Rod Bundles after Ballooning.
Li 3rd Part: Cladding Oxidation. Resistance to Quench and post Quench Loads. Safety Criteria.
SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 2 a (>
'g""' - IRSN State-of-the Art Review on LOCA Clad Ballooning and Rupture Flow Blockage Fuel relocation SEGFSM Top. Meet. on LOCA Issues, ANL May 25-2 7, 2004 3 at,.
CLAD BALLOONING and RUPTURE / FLOW BLOCKAGE OUT-OF-PILE TESTS IN-PILE TESTS SINGLE ROD MULTI ROD SIGLE ROD MULTI ROD EDGAR (CEA)
PBF-LOC (INEL) PHEBUS (IRSN)
KfK OREBEKA) Kf (RBEKA)
FR2 (KfK) NRU-MT (AECL)
EOLO-JR (Ispra) TREAT FRF (USA)
JAERI JAERI FLASH (CEA)
ANL BCL KWU KWU UKAEA UKAEA Westinghouse Westinghouse SEGFSM Top. Meet. on LOCA Issues, ANL May 25-2 7, 2004 4 i.,
L ,BALLOONING / BLOCKAGE. Main Findings (1A)
Out of Pile Single Rod Tests &lleading influence of azimuthal AT
- Direct heating (EDGAR) or internal heating and heated shroud (KfK, ORNL...)
0 azimuthally uniform temperature 4 large circumferential burst strains ( up to > 100%)
- Internal heating with unheated shroud W>non uniform temperature 4 low average burst strains process linked to the anisotropy of a-Zircaloy (" hot side straight effect ")
. 120 F 1T 4-
& SMALLAZIMLMTAI. RW sn-ls 100
- AG~l~T Ir~SWu 80 - ---
A TYPICAL BUNDLE VALUE
- ORNL A LRESIS(A 60 - M i RNC9 i At A A RES_
~A A
£A A *~ AZIMUTAL Blue sy,,ba A fRADINT' nonheated shro.d s 20 4 LA LA 0
600 700 800 900 1000 _EEK A_____ta____
BUBrS 'rE.MPEATLJRE OC - singlerodtests.C kurvlC SEGFSM Top. Meet. on LOCA Issues, Oso oo ANLMay25-27, 2004 aimuIthl claddog temperatire dferenct AT_ K 5
. (.
IR El BALLOONING / BLOCKAGE. Main Findings (1B) 0 Out of PileSingle Rod Tests Oleading influence of azimuthal AT Modeling of strain and burst
- ID : mean strain, deduced from an "average" of experimental results (ex: NUREG-630) burst criteria: average stress = f(T) (-> CATHARE versions up to VI1.4,...)
o2D : strain azimuthal profile
-> allows to take account of ATaz burst criteria : maximum local strain
(-* FRETA,...)
0 10 20 30 40 60 Aikm&"hal bedsE iffey"(p SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 6
MKOL WnM 9%
BALLOONING / BLOCKAGE. Main Findings (2)
Multi Rod Tests X influence of thermal and mechanicalinteractionsbetween rods Tests: ORNL MRBT (4x4, 8x8) and JAERI (7x7)
W large deformations of inner rods 4 contact on peripheral rods before clad burst q axial extension of straining and blockage 100 so -5 w a-0 80 20 3 00 M2 0s2 40608 I
~GRID 1 ~ 'GI 00 SPACER SAER 20 40 60 80 ¶00 DISTANCE ABOVE BOTTOM OF HEATED ZONE (cm)
ORNL Recomman~dation (Chapnman. 1982) :bundle tests : at least 2 ring's oftuard rods are required to reproduce representative conditions of thle inner rods in a reactor assembly SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27.2004 7
Ilt AMM, KSb A BALLOONING / BLOCKAGE. Main Findings (3)
Multi Rod Tests LO influence of guide tubes .400-1U Test REBEKA-4 (5x5 bundle with unpressurized rods in outer ring) --- <94-\W. CON. R.----.R
- Test R-4: smax 79% on a rod neighbor of G.T. D ~ST.::5.0 g/nt%m
'I00. ... HR.:1.0 R. t° ---
x * I i 2 f
!No. 20 O JAERI Tests 21 to 24 ( 7x7 bundle) with 4 G.T. I-1 CO R I
- RI a
q presence of G.T. does not reduce, and even :I.
US N .ST.:-5h4 gltrnmM'~~~
us
'HRA1.'trs ',N . . j; increases strain on neighbor rods, despite large ATZ -300 do 1i- - - * -- r -- - -- ---- - - - -
(57°C in REBEKA-4, 71°C in JAERI-24) -200
-_wa KfK explanation : stop of "hot side straight effect" due to contact of deforming rod with GT (for w<20%), 400 then gap re-opening on hot size in in in; o CHANNEL BLOCKAGE tZR in i
-+ ATaz reduction -+ increase of burst strain O Modeling: importanceto describe thermal (radiative) and mechanical (contact) interactions between rods and rods and structures SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27. 2004 8
BALLOONING / BLOCKAGE. Main Findings (4)
Multi Rod Tests ZO influence of thermal-hydraulicconditions partially illustrated by NRU MT-4 vs. MT3 tests (32 full length rods, 12 inner rods pressurized)
MT-3 early reflood, clad rupture under 2p cond. I MT-4: late reflood, rupture during heat-up under steam a", 3 akw Axial distribution of strain in NRU MT-3 and MT-4 tests (x unit= inch)
Deformations appear significantly coplanar, due to the homogenizing effect of grids and not much different (maximum value, axial spread) in MT-3 / MT-4 (....as opposed to REBEKA 6 / 5 results) v-Two-phase TH influences on blockage are complex and difficult to foresee and transpose at # scales SEGFSM Top. Meet. on LOCA Issues, ANL May 25-2 7, 2 004 9
~~~I eat BALLOONING / BLOCKAGE. Main Findings (5A)
In pile tests with irradiatedfuel rods influence ofpellet/cladgap reduction or closure duringpriorirradiation ( N azimuthal AT)
Li PBF-LOC Tests:+ increase of circumferential burst strain on irradiated rods (<16 GWj/t) /unirrad.
(I x 2). laraer axial extension and clad thinning over whole circumference
_ B~ S '-llc8wcl
." I 10, 1000_
C u0 I' I
I. 40 I
- C cJ
-100 e Ci GA OA GA Distorms from bottom of fuel stock (ri) a1t> K U:tsd Acei toww.iv. "W0lated SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 10
go c6ift
-17 BALLOONING / BLOCKAGE. Main Findings (5B)
In pile tests with irradiatedfuel rods (cont.)
C FR2 Tests:4 no apparent effect of irradiation on clad deformation nor apparent sensitivity to azimuthal AT may result from particular irradiation C
.a 100 conditions in FR2 4-tn 80 (low T and P -> no clad creepdown)
.4 with additional effects of axial VW
'4-constraint due to spring, limiting U_ 4C hoop strain, and of the closeness of L._
shroud to test rod, limiting rod bowing v0 20 40 60 80 100 1K]
Maximum azimuthal temperature difference at burst elevation.
SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 I11
BALLOONING / BLOCKAGE. Remaining Needs.
In pile tests with irradiatedfuel rods (cont.)
El No bundle test with irradiated rods carried out up to now what could be the cumulative effects of irradiationand bundle size on blockage ratio?
On the basis that:
>Burststrainfor PBF-LOCfreshrods ;' ORNL Single Rod, unheated shroud
>Burst strainfor ORNL Multi-Rod >> ORNL Single Rod, unheated shroud
>BurststrainforPBF-LOCirradiatedrods >> PBF-LOCfreshrods I INEL recommended to perform bundle tests of sufficient bundle size with irradiatedrods (J.M. Broughton, Sun Valley, 1981)
According to the known effect of H charged during irradiation on clad mechanical properties (shift of transus temperature Tcs+,p -; significantreduction of burst strainfor high BU irradiatedZircaloy (~ 600 ppm H), see EDGAR results on pre-hydrided Zy) 0> we expected the issue to concern more specifically irradiatedfuelrod claddings with low H uptake under irradiation(low burnup Zy4, BWR alloys or advanced PWR alloys at high BU)
But recent results (see presentationby N. Waeckel) indicate this may also concern high BUZy4 SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 12
IMM ASC FUEL RELOCATION. Main Findings (1)
In pile tests with irradiatedfuel rods (cont.)
iZ fuel relocationobserved in PBF-LOC, FR2, FLASH-5, ANL-Limerick tests with irradiatedfuelrods (2.5 < BU < 56 GWj/tU)
A.
FRESH FUEL ROD Test B 1.1 VJ 1-'.1
- .4--
l "AIr1311X, I: Q:I.,, . .."I 35 GWd/tU ROD Test G 8.2 SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 13
FUEL RELOCATION. Main Findings (2)
^ aSp"2 Main c. parameters:
- instant of fuel collapse ViS>w End of
}likely near tbust at least for low BU (FR2: E3 & E4)
/ fragments granulometry heterogeneous at high BU (see ANL test ICL2)
X- % will enhance filling ratio T136- _TA illing ratio may be altered during post test handling (PBF-LOC)
Impact Rod Fl1 .
local heat generation and transfer to clad P__-TRIEN_ P raises T and ECR (for observed fill. ratios)
FR2 rod Fl (20 GWj/t) r may affect secondary hydriding conditions SEGSM Top. Meet. on LOCA Iss ANL May 25-27, 2004 1st objective of Halden LOCA tests 14
Moa 199a w FUEL RELOCATION. Main Findings (3)
Fuel chunks relocation Filling ratio as a function of burst strain 90 80 70-a 0 X A 60 GO 0 PBFILOC-gammascannini Si(7SMIRT)~ l
.o 50
- PBFILOC-mnicrographies A FR2/E5(KfK-3346)-slow depress.
- ) 40
._
- FR2IE5(KfK-3346)-divergent cone IL
-experimnental upper boundary 30 1 O El-Shanawany(Glasgow88)-base case l El-Shanawany-sensitivity 20 O Edf X,k. IRSN-base case 10 -
0 0 10 20 30 40 50 60 70 80 Burst strain (%)
SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27. 2004 15
I "U. IRSN State-of-the Art Review on LOCA Coolability of Flow Blockages Due to Clad Ballooning under LOCA Transient Conditions SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 16
1 L Effect of Clad Swelling Upon Assembly Cooling 0k investigations on cooling under LOCA reflood conditions of a rod bundle containing a preestablished partial blockage region Li Common Experimental Characteristics Bundle of electrically heated full length rod simulators, with a group of rods bearing a pre-shaped deformation over a given axial length (- pre-determined blockage ratio )
- establishment of steady state initial conditions in steam (Tg 600 to 800'C)
- heating power residual power NB: no power increase in the ballooned region of heated rods, and large gap 0 run of a liquid reflood transient under forced or gravity reflood conditions 4 impact offlow blockage on coolability evaluated upon comparison of clad temperatures in the blockage and by-pass regions SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 17
I>; [S] FLOODING EXPERIMENTS WITH BLOCKED ARRAYS Specific Experimental Programs
- FEBA (KfK, Germany)
. 5x5 rod bundle; Lheat=3 . 9 m; "conventional" simulators; forced reflood
. Blockage over 3x3 or 5x5 rods; x=62% or 90% ; thick sleeves; LB i= 65 mm (90%/0)
- SEFLEX (KfK, Germany)
. 5x5 rod bundle; Lheat=3 .9 m ; REBEKA simulators ; forced reflood
. Blockage over 3x3 rods; x= 90%; thinned cladding (e - 0.5 mm); LB=, = 65 mm (90%)
- THETIS (AEA Winfrith, UK)
. 7x7 rod bundle; Lheat=3 .6 m; "conventional" simulators ; forced or gravity reflood
. Blockage over 4x4 rods; x=80% or 90%; thin sleeves (e 0.3 mm); LBmax= 200 mm
+ CEGB (Berkeley, UK)
.44 rod bundle; Lheat 1 m ; blockage over 4x4 rods; x= 90%; LBm = 147 mm; forced reflood
- FLECHT- SEASET (W. USA)
- 21 and 163 rod bundles; Lheat- 3.66 m ; forced or gravity reflood
- Short concentric sleeves, coplanar or not; long non-concentric sleeves, non-coplanar SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 18
PINNIN.
9-72 Mw 9%
WI, I.",
FLOODING EXPERIMENTS WITH BLOCKED ARRAYS FEBA and SEFLEX Main Results 00000 0.
FEBA VI
~00000 I
,I FEBA Test section ; Blockage 90% on 3x3 rods SEFLEX He gap SEFLEX Ar gap 71it. S needing rte 3.8 eot Met ,el 2D25 Sstem pressre 2.1 bar MR rot boot ROOM8 tol bentLt V Mem. re etwiEfI SEFLEX Test section; Blockage 90% on 3x3 rods E Slekeg..
+ 2teka.
,Leee.
ut ret wdorruoth &teo" edding a sekege.
X tscka#
rodnt ddl It hooter l*:@t Temperatures at the blockage midplane SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27. 2004 19
COOLABILITY OF BLOCKED REGIONS Main Findings (1)
The evolution of temperatures within and downstream of a blockage region results from the combined effects of:
> the by-passing of fluid flow towards the unblocked flow channels qk significant reduction of flow, then of cooling capacity (under similar lineic heat flux)
> penetration of liquid droplets inside the blockage (due to inertia) impact of droplets on balloon walls, fragmentation, re-entrainment in finer droplets, increase in turbulence 4 71 liquid / vapor heat transfer (vapor de-superheating) 4 enhanced cooling of walls (at least for short blockages)
> possible fall of droplets at the blockage outlet (widening section)
I dispersion and evaporation in steam jets 4 enhanced cooling (at least for short blockages)
SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27. 2004 20
COOLABILITY OF BLOCKED REGIONS Main Findings (2)
Blockage representativity (thin vs. thick sleeves) observed from SEFLEX / FEBA tests results SEFLEX: lower heat capacity of the balloon walls and low coupling with heater q early rewetting of the balloon, propagation of secondary quench fronts up- & downstream
> FEBA results conservative /reactor rod balloon with fresh fuel (notfor irradfuel)
( Influence of flow restriction and blockage length FEBA (90% / 62% ; LBIOCk= 65/125 mm), THETIS (90% / 80% ; LBIOCk= 200 mm)
- FEBA 62%: blockage always better cooled than by-pass region
- FEBA 90%: low penalty (+40'C on Tn= at blockage outlet) for VflOOdni = 3.8 cm/s
- THETIS 90%: coolability limit for Vreflood < 2 to 3 cm/s
- 80% blockage ratio : better cooled than 90% for high Vreflood, opposite for low Vreflood (2 cm/s)
Influence of blockage length 4 linked to penetration and length of influence of droplets q highly dependent on flow blockage ratio and T.H conditions : flooding velocity and lineic power SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 21
COOLABILITY OF BLOCKED REGIONS Main Findings (3) c0 Influence of the blockage configuration : coplanar / non coplanar
> FLECHT SEASET 21 rods, short balloons (low axial overlapping) under non coplanarconfiguration:
- the flow redistribution around one balloon increases local turbulence, then cooling of neighbor rods,
- but the isolated influence on droplets fragmentation in the adjacent channel is lower than in coplanar configuration IInfluence of the nature of reflood (forced I gravity)
> THETIS tests, 80% blocage ratio, forced / gravity reflood
- rapid oscillations of inlet flow and liquid level under gravity reflood, vanishing after 90 s
- temperature evolution, in blockage and by-pass, very similar to those in comparable forced flow G Influence of the presence of a by-pass region or not
> FEBA tests, blockage 3x3/5x5 ; FLECHT SEASET 21 rods (config B/ config C) tests without by-pass non representative : no flow redistribution =:> velocity increase in the blockage, thus enhanced cooling / configuration with by-pass SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 22
COOLABILITY OF BLOCKED REGIONS Pending Questions El Impact of fuel accumulation in the balloon (fuel relocation)
- EXISTING: analytical tests on bundles of electrically heated fuel rod simulators with partially blocked regions bearing pre-shaped balloons, large heater/clad gap cheaters are fixed and heating axially uniform (inside / outside balloons) significant differences between results of comparable tests FEBA and SEFLEX
> underlines the large impact of thermal coupling between the heat source and the ballooned cladding I The impact of fuel relocation in fuel rod balloons, as was observed in all in-reactortests with irradiatedfuel, leading to an increase in local power (lineic and surfacic) as well as a very reduced fuel-clad gap, on the coolabilityof the blocked region, is stillfullyquestionable and should be addressed by specific analytical tests with a simulation of fuel relocation.
SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 23 I
CONCLUSIONS. Pending Issues EJ Flow Blockage in a Bundle of Irradiated Rods
- No multi-rod burst test with irradiated fuel available up to now q Such tests (with low H uptake clad material ?) would be of main interest El Fuel Relocation
- Instant of fuel collapse, granulometry and filling ratio at high BU q Halden single rod tests (IFA-650)
LI Coolability of Blocked Bundles with Fuel Relocation
+ Open question, particularly for long balloons and low reflood rate, for which the blockage ratio still coolable might be less than the widely accepted value of 90% derived from FEBAISEFLEX tests results.
4 Need of specific analytical tests with a simulation of fuel relocation (representative lineic power and gap)
SEGFSM Top. Meet. on LOCA Issues, ANL May 25-27, 2004 24 I