ML19305B302
| ML19305B302 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 03/10/1980 |
| From: | GENERAL ATOMICS (FORMERLY GA TECHNOLOGIES, INC./GENER |
| To: | |
| Shared Package | |
| ML19305B299 | List: |
| References | |
| GA-D15369-ERR, GA-D15369-V01-ERR, GA-D15369-V1-ERR, NUDOCS 8003190483 | |
| Download: ML19305B302 (4) | |
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The model exhibited various different types of response as the controlling parameters in the system were varied.
Although it is diffi-cult to categorize the types of response at this stage, the motions observed may be considered to fall within two major groups:
(1) low-amplitude fluctuations and (2) fluctuations with impacts.
1.
Low-Amolitude Fluctuations.
When the cross flow area is sufficiently large, such that the flow resistance in the horizontal channels is relatively small, the lateral AP is minimized.
In this case, the motions observed were charac-terized by periodicity of response with small displacement amplitudes without impacting adjacent structures.
No boundary impact forces were developed, and dowel loads were negligibly small.
In these examples, the lateral AP across individual blocks was less than 0.5 psi.
2.
Fluctuations with Impacts.
When the cross flow area was 7
reduced significantly, the model could again be dynamically excited when core 6P exceeded a particular value.
In these cases, the lateral AP across individual blocks reached up to 2 psi.
Thus, the fuel regions and reflector columns showed more significant motions with impacts against one another.
The preliminary results described above are strictly qualitative at this time.
However, the results do exhibit the characteristic of block j
motion, which has been inferred as necessary to explain many of the observations during fluctuations.
One characteristic, where the analyt-ical model appears to differ greatly from the observed results, is the period of the fluctuations.
The analytical results indicated a fluctu-ation period of M see or less, whereas the observed fluctuations had a period of.M 0 to 20 min.
Therefore, it is premature to draw any conclusions regarding the correlation of the analytical model to the observed fluctuations.
8 0W M 4-129
4.7.3.
Core Barrel Model A three-dimensional thermal / structural model of the core barrel was developed. The purpose of this model is to examine the distortions of the core barrel caused by nonuniform temperature distributions.
The model is illustrated in Fig. 4.7-9.
The thermal model includes radiation from the side reflector. as well as convection from the gap coolant flow between the reflector and the barrel.
The structural representation of the barrel uses three-dimensional finite elements.
The first case investigated with the model was the effect of the flow blockage downstream of the T/C penetrations.
The deformation of the barrel was found to be very sensitive to the boundary conditions at the bottom of the barrel.
The barrel has a potential for a 20.25 in.
ovalling.
The effects of the boundary condition, core barrel keys, nonuniform heating, and friction are to be investigated.
If the potential for ovalling can be demonstrated, then the thermal feedback
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loop will be added to the model to determine if a fluctuation mode exists.
4.7.4.
Two-Dimensional Side-Reflector Model A two-dimensional model of the side reflector and core barrel was developed. The purpose of this model is to investigate the overall thermal and pressure effects on these components.
The model is illustrated in 1
Fig. 4.7-10.
This model includes thermal respone of reflector and core I
barrel, heating of the gap flows, and the thermal and pressure distor-tion of the structure.
Results from a first version of the model, with one-dimensional flow, were inadequate.
Consequently, a two-dimensional flow network was added to the model.
Possible laminar / turbulent tran-sition in the reflector to barrel gap flow can be investigated with this model along with thermal / mechanical feedback.
4-130
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BOTTOM Fig. 4.7-9.
Finite element model of the core barrel 4-131
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Core barrel / side reflector model 4-132 l
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