ML20147B513

Forwards Pages Omitted from Ninth Monthly Rept by NRC Resident Engr at Kernforschuugszentrum,Karlsruhe,Ge

ML20147B513
Person / Time
Issue date:	06/28/1978
From:	Johnston W NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
To:	NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
References
NUDOCS 7810110034
Download: ML20147B513 (4)

Text

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g6 UNITED STATES Edqtts. PDIt

, pp 'i - k; NUCLEAR REGULATORY COMMISSION

• g' j WASHINGTON, D. C. 20655 2ES

%*****/ ,

JUN 2 81970 Those on Attached List

Subject:

Ninth, Monthly Report by NRC Resident Engineer at Kernforschung- ,

zentrum, Karsruhe, Germany ,

Gentlemen:

The enclosed pages (replacement pages 2 and 3) were inadvertently omitted in the typing of the last (ninth) monthly report.

Sincerely, Y{<Y Nh W. V.'dohnston, Chief Fuel Behavior Research Branch Division of Reactor Safety Research i

a

E .

G.-. - -

. ~. e = =accr:>.m. ;

(2)

. ~

(5) 7. Dullfores, J. Reynolds, and R. Peekover, ' Interface Temperature ,

Criteria and the Spontaneous Triggering of Sman-Scale Fuel-Coolant Reactions". .

ne authors censidered te=perature interaction zones for low melting fuel '

simulants to determine the temperature regimes within which spontaneous triggering might occur. These interaction zones. co= pare wen with exper-

. iment. The theory was then extrapolated to the UO /Na 2 and steel /Na systems to deterr.ine the maximum size of the temperature regimes for spontaneous triggering.

(6) H. Goldar=er, H. Hohmann, H. Kottowski, and M. Mol, " Simulation of the nermal Puel-Coolant Interaction in Imboratory Tests for Water Cooled -

Reactors". These experincnts have been previously reported. In sum =ary:

explosiens have been repeatably produced in a shock tube (mass up to 150 gram, pressures to-25 bars), but have not yet been produced in a tank faci-

. lity. ,

(7) G. Fieg and H. Werle, "Model Experiments on the hermodynamics of Core Meltdown". Rese experiments were conducted at KfE to study the be-havior of convection cells and melt-front expansion in a soluble bed. ,

i The correlatiens of Mayinger and Eaker were not wen' confirmed measurement errors).

by the convection Further experimentseen areexperiments (discrepancy required to explain the > discrepancy. - l In the melt-front experinents it has been shown that the radial advanca is almost independent of density ratio, whereas the vertical ad-vanec is deedsively dependent on this ratio. When the densityiof the bed is lower than that of the melt, conventional convection cell theory is in

. Food agreerent with experiments. This is not tme, however, when the den-sity of the bed exceds _ the density of the melt, l (8) H. Reincke, L. Rinkleff, and R. Schramm, " Heat Transfer between Molten Core Material and Cenerete". This paper describes the discrete bubble medel, which has been previously reported in this series.  !

_ _ _ _ _ l (9) W. Doerr and M. Peehs,"Therr.a1 Properties and Besistance of Beactor l

Concrete with Respect to Core Meltdown". Effective heat capacity as a  !

function of temperature was measured by a calibrated laser heating method, i C

'Jfg/K at 11000 C.ofThe silica concrete themal varied was diffusivity from also 0.9 J/g/K measured at roomastemperature a function to 1.88 l of temperature, and from this a thermal conductivity varying from 0.016 W/cr./K at 50 C to 0.011 W/en/K at 300o C. Silica concrete shows excellent excellent themal shock resistance.

- Tests of silica cenerete with heated cordum and corium consti-tuents showed that the attack of a prototypical melt on concrete is yurely thernal no chemical or metallurgical reactions occur that might lower the melting point.

he illustrations in this paper are unfortunately very small and not suited for reproduction. nermal expansion, density, conductivity, heat capacity and diffusivity are given.

(10) K. Massmann, J. Artnik, M. Peehs, and P. Hosemann,"The Significance of Pydrogen Formation in Fypothetical Core Meltdowns". Following experi-ments on reactions between metal melts and gases liberated from concrete, the oxidation reactions were modeled. Be simplifying assumption of 100%

reduction of the liberated gases was made. Reaction kinetics were ignoredg i their effect shgald bo h __ . _ - - . - - - - - ---- - - - - - - - - - - -

l

(3) .

Calculations of the attack of a core melt on the reactor base mat indicated that for the first day, E, would be added to the containment.

hereafter, only water vapor would be IIberated. We exothermic reactions lead to about 50 C increase in temperature after the initial cooling.

Pressure increase in the containment was computed both for con-tinuous burning of the H2 and for sudden, massive burning. Containment pressures reached 4 bars with continuous burning and 6 bars with massive burning, hese pressures are lower than those assumed for bursting of a German PWR containment.

We transactions of Reaktortagung 1978 include 267 papers covering reactor design, safety, fuel cycle, fuels and fuel elements, components, construction and operation, fusion technology, and economics. The piblisher is Deutsches Atomforum, E.V., Heussallee 10, 5300 Bonn.

1

3. Fuel Rod Behavior Research.

The isothermal steam oxidation of Zirka11oy has been experimen-tally investigated by leistikow, Schanz, and von Berg /1/ at -KfK (IFS).

Tne tenperature regime investigated was 700-13000 C. The following equations describo the kinetics of oxygen uptde ( t), growth of the oxide layer ( y),

%-layer (ct), and of the oxide plus o(-phase double layer ( {):

T =.724 6 exp(-10481/T) h =.2806 exp(-10107/T) c4 =.713 6 exp(-10961/T) h =1.29 h exp(-11043/T),

where t is time (see), T is temperature (K), and of, h,j are in em.

he results are compared with the Paker-Just approximation in

. Figure 1 (p.6 ). It can be seen that the Baker-Just relation is quite conservative, and that this conservatism increases with increasing temper-ature.

/1/ S. Leistikow, G. Schanz, and H. v. Berg, Xinetik und Morphologie der isothermon Damer-Oxidation von Zirealey 4 bei 700-13000 C, EfK 2587, Kern-forschur.gstentrum Karlsruhe GmbH, Parch,1978 ',

4 Forthcominc Events g Interest.

Readers are reminded of the Topical Meeting on Nuclear Pcwer Eeactor Safety, to be held at Brussels, Belgium, October 16-19, 1978

5. Miscellaneeus.

Ly agreement with Dr. W. V. Johnston, the reporting period will in the future be bimonthly. In special circumstances (e.g., when very im-portant results need to be urgently reported), the period will revert to a monthly basis, l

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