ML19305B305
| ML19305B305 | |
| 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-D15369-01, GA-D15369-1, GA-D15369-V2, NUDOCS 8003190488 | |
| Download: ML19305B305 (2) | |
Text
.
s 4
uo3oC.
NCn Jcm Ncm 2
.c4 A
C z2 3"
E fy.
2$
C m-j%
M=
4
.u b
_ g
,euo e
Q b
R wc ce w
E u
R $
s E
e
.o.e uoc 2
=
w e
as d
o 2
w=
aeuo Ia 1
a a
a
.e4 aso
?
I t
I f
f a
g a
R g
o
=
=
=
=
g g
2 o
(Jo) 3Hnivuldn11131100 N0103U I
h t<
e d
2 A
8003190 ' [ b i
- -?
~
r 5.4.2.
Analysis and Theories Several studies have been made in an effort to understand this camperature retrograde phenomenon in Region 34.
In late 1977, Region 34 orifice asse=bly was removed for inspection and reinstalled.
Initial measurements indicated the orifice calibration for this region to be different before and af ter removal of the assembly.
This, along with the temperat6re retrograde, prompted a detailed study of Region 34 (Ref. 5.4.3).
Possible explanations explored in this study included the following:
1.
Misalignment of the Region 34 valve during the initial assembly could have opened gaps, reducing the closed valve loss coeffi-cient and the valve sensitivity.
This misalignment was corrected (unintentionally) during the subsequent removal and reassembly.
s 2.
Crossflow gaps could exist at the top of the core.
It is not obvious how and where these gaps exist, but it is speculated that such gaps exist for the purposes of explaining some of the observed phenomena.
3.
Tilqing of columns to open several crossflow gaps at the lower axial positions in the core (i.e., at the core support block /
bottom reflector block interface) could have reduced valve-loss coefficient and valve sensitivity.
In addition, crossflow gaps at lower axial positions in the core could explain the tempera-ture retrograde phenomenon af ter a valve adjustment.
4.
Since Region 34 is a rodded region, its radial power profile has a dip at the region center so that the region periphery is at a relatively high power.
Region 34 flow control valve is at its near-closed position and is expected to starve the region 5-96