ML20076J861
| ML20076J861 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/30/1978 |
| From: | Rosalyn Jones BABCOCK & WILCOX CO. |
| To: | Dunn B BABCOCK & WILCOX CO. |
| References | |
| TASK-*, TASK-GB GPU-0614, GPU-614, NUDOCS 8307060523 | |
| Download: ML20076J861 (3) | |
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THE SASCOCK & WILCOX COMPANY
. POWER GENERATION GROUP To l
B.M. Dunn,' Manager, ECCS Analysis From R.C. Jones, ECCS Analysis (2066)
N H3.5 Cust.
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File No.
or Ref.
Subj.
Date March Activities Report March 30, 1978 lm.i.........,..................w,.
Supervisory Engineer - R.C. Jones Engineers - W.L. Bloomfield l
J.R. Dieterman M.G. DiQuarto M.A. Haghi C.W. Jones N.H. Shah i
I.
Acco=clishments l.1 Scheduled Activities a.
The 6-foot auxiliary feedvater (AFW) level control on the 205 l
j FA plants has been determined inadeouste to control the con-sequences of small break transients.
During this month, the analysis of both the 0.05 ft pump suction break and the 2
0.05 ft2 pump discharge break were completed.
For the pump suction break, it was determined that the core remained covered throughout the transient. Core uncovery was calcu-lated for the pump discharge break starting at %1500 seconds.
Long term cooling for the discharge brea k was established at b
%2600 seconds.
The two-phase mixture 1 vel in the core at -
N that time is less than 8 feet.
Simple hand calculations in-dicate that the fluid temperature at the top of the core b
would be in excess of 1600F.
It is improbable that the peak M
cladding temperature would be less than 2200F.
The results p
of the analysis are documented in the memo N.H. Shah to D.H.
i Q
Roy, " Status of 205 FA Small Break LOCA Analysis," March 29, 1978.
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J During this month, a method of extrapolating the transient l
k N
system pressure and core liquid level responses by hand,
%q once the " boiling pot" mode of the small leak transient has
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been established, has been developed by N.H. Shah.
This
[*E method results in a significant savings in computer time with j,Si, 8, little sacrifice in accuracy.
d j $ 8E Additional information on this subject is given in the " Prob-L y,9.!E lems" section.
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1 March 30, 1978 B.M. Dunn b.
The EPRI Tight Packed Lattice work continued this month.
In-formation pertaining to heat transfer in a vire wrapped lattice appears hard to find.
Generally speaking, it appears that the heat transfer models presently in CRAFT and THETA would be con-servative by %10%.
Contact was e.stablished with Art Lowe, Technical Staff, and he has agreed to provide the latest infor-mation on rupture characteristics of stainless steel.
A slight problem was discovered in keeping the reactor subcriti-i cal during the reflooding phase of the LOCA.
Fuels Engineering was not aware that this must be assured.
Resolution of this
-problem is presently underway.
The review of the ECCS evaluation model to determine changes c.
necessary for a Conn Tankee calculation was put into a temporary hold this month due to illness of the responsible engineer.
This will be picked up next month.
1 The review of the in-house information on Conn Tankee was con-tinued this month. A list of additional drawings necessary to construct the LOCA model were sent to NUSCO this month.
d.
The impact study of the new Mark-C fuel design on the LOCA analysis is continuing.
The CRAFT run has been completed and it has been determined that the REFLOOD run need not be re-peated for the new fuel design. The THETA model has been com-plated and is presently under review.
a.
Work on the 0.04 ft2 pump discharge break on the 177 FA lowered loop plants is progressing slowly.
At present, CRAFT results have been obtained for the first 1000 seconds.
Due to the support work on a higher priority item and computer problems, it has been difficult to obtain results in a timely fashion.
1.2 Unscheduled Activities 1
Round 1 questions on Consumers have been received.
Manhour and a.
computer hour estimates have been provided to respond to these questions.
Responses to the majority of the questions will be provided in April. This will result in some slippag'e on the Tight Pack Lattice and Conn Tankee work.
l b.
Provided J.J. Cudlin information to re pond to an NRC question l
on best, estimate values of various LOCA input parameters.
Responded to intervenor questions on PGE.
c.
d.
Work was started to respond to NRC question on the effect of loss-of-offsite power at some time during the LOCA.
A special version of REFLOOD was created for this study and a run has been made.
At present,'the REFLOOD results look strange.
Due to support work provided on the 205 FA AFW 1evel control study, little additional work could be performed this month.
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~B.M. Dunn March 30, 1978 e.
Questions on the'CET response predicted for Standard Problem #7 were received.
The NRC is concerned about the overprediction of the CFI delivery flow and the possible non-conservatism in the I
ECCS evaluation model.
From a prel4=fn=ry investigation, it appears that the overprediction in delivery is caused by an un-derprediction in the injection leg pressure.
Once the flow is corrected for AP, the predicted and measured flows are in good agreement.
II.
Problems As mentioned in 1.la, the present 6-foot AFW level control on the 205 FA plants is not sufficient to keep the core coolable for small breaks.
It is recommended that a Risk Program be developed on this area.
Design changes and/or operator actions must be inve.ciga ed to find a solution to this problem.
Additional funding and time wiL. be required to com-plate this study. This will have an inpact on the present ECCS schedule.
III.
Resolution of Previous Problems There were no previous problems.
IV.- R&D Progress See attached R&D quarterly progress report.
V.
Administrative C.W.' Jones was on a leave of absence this month.
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