ML19323F844
| ML19323F844 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear, Crane  |
| Issue date: | 08/05/1975 |
| From: | James Anderson ARKANSAS POWER & LIGHT CO. |
| To: | Cavanaugh W ARKANSAS POWER & LIGHT CO. |
| References | |
| TASK-TF, TASK-TMR JWA-1373, NUDOCS 8005290534 | |
| Download: ML19323F844 (2) | |
Text
E I
A.RKANSAS POWE!A G. LIGHT COMPANY INTRA COMPANY CORRESPONDENCE Arr.ansas Nuclear One Russellville, Arkansas August 5, 1975 JWA-1373 hS1CRANTRI TO:
William Cavanaugh III FRG!:
John W. Anderson, Jr.
SUBJE C:
ARKANSAS NUCLEAR ONE - UNIT ONE PRESSURIZER LEVEL LNDICATION FOLIHKING REACIOR TRIP File: 0270.83
REFERENCE:
Letter Govers to Cavanaugh July 24, 1975 Same Subject Ccncerning B5W's letter of 7-24-75 relating recc=nendations to provide a solution for pressurizer level dropping belce indication on reactor trip, we have the following commnts, f(
Item 1 We concur that it would be nice that Tave not fall balcw 548 F.
We do not ccncur that this can be acconplished solely by resetting our main steam safeties. Further, we believe that the blowback of the wa.'. steam safeties has been cptimited through several atter n resetting the amunt of b1cwback in the early phases of &
s startup test prog am.
It is possible that some drift has occurred since the last se,i. ting; but since resetting of bice-back is largely a trial and error process, it is likely that an atterpt at change might worsen rather than improve the present b1cwback.
The B4W 1etter fails to relate differences in F.W. flow following the two trips discussed. It has been ncted that excessive F. W.
flows following a trip can drive T dcwn just as effectively as c
lowering turbine header pressure.
It is felt that the ICS system design, which allcws a runback of F.W. after trip at normal tracking rate (20%/ min.), is a major contributce to the excessive shrink noted in our system. Even though the main and lo-load block valves trip closed rapidly cn a trip, far too much F.W. flow is driven through the full-cpen S. U. valves which will not modulate to hold lo-level limit cn the OTSGs until the F.W. demand signal is run back to belcw the lo-level limit valve. Tnis does not occur until 4 minutes follow-ing the trip.
8 00529 c5.34
afr. Cavanaugh
~
August 5, 1975
{
JdA-1373 Page Two Excessive F.h. ficw also creates excessive blew time of the M. S.
safeties, which tends to lower their lift and reset points.
The Operatiens group suggests that the S. U. control valves be placed in manual and reduced to :10% demand (after the main F.W.
ilocks are cpened in the course of plant startup).
If a trip occurs, the F.W. ficw will decrease at whatever rate the main and lo-load blocks will travel closed dcwn to the minimu:n pre-set value.
Hopefully this would provide data to demonstrate our contentions.
A long-term solutien, such as instantaneous ICS runback on RX trip, could then be pursued.
Item 2 As pointed cut, these differences could be due to F.W. flow differ-ences between the two trips.
Item 3 We disagree; we do not want an unnecessary E. S. actuation to the s~ ~~ ~ sc:= dcn't want the unnec:
<ry HPI nozzle thennal cycles. See note belcw.
Item 4 We wholeheartedly disagree; this would eliminate any possibility of surviving load rejecticn, or loss-of-pumps nabacks.
Note:
If operatiens were prcvided with wider range pressuri::er level indica-tion, the standby E. S. pump wouldn't be started.
JWA:EC:BAB:mcc CC:
J. H. Wocdward N. A. Moore T. H. Cogburn B. A. Baker i
^.. - _ ~. _ _ _. L - _ =_ _. _ _
m.=
-n?m_. K z e
,w.=-
'L**
-