ML20090D779
| ML20090D779 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 09/03/1971 |
| From: | Schneider F NIAGARA MOHAWK POWER CORP. |
| To: | Morris P US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 14489, NUDOCS 8303020358 | |
| Download: ML20090D779 (2) | |
Text
,
u m
p O
O' 4*
(L~.
NIAGARA MOHAWK POWER CORPORATION S
&~
- 5. * '
NIAGARA MOHAWM
- g A.
300 ERIE Sout E VARD WEST
\\
SemacuSE se v 3202
%?q k"- [ -
Sept ember 3 19 '.
8b Dr Peter A Mo rris, Di rec tor Division of Reactor Licensing United 5tates Atomic Energy Commissian hashington, a C.
20545
Dear Dr. Morris:
an J une 19, 191, with the Nine Mile Point Nuc l ea r -t at l an p roduc -
Ing 456 Mh.g), the condut t ivity of the wat e c in t he reattor ve c el.n.reased to su mmho A-this
- imit ing condit un for nee it tor an o rtte <
-nut-down wa3 b e gur. In fi f t v s1x minut es of the oc current.-
Spectf4
.it s -.sii cold for an orderly snutdown started within an hour and the rea( t e r tc "e
shutdown in ten hours.
wa3 found that one of the andensat e During the load reduc t ion, it storage tank's conduct tvity was approx 2iitately 250 mmho, the other 25 One hour and thirty four minutes after the beginning or load reducti-n. tne con trol rod drive pump supply water was t rans ferred f rotr the conden-at e 3t o rac t ank t r the diminerall:cd water storage t a4 and a -e cond e l e tn - e pumn u s st arted to increase purificat ion of the reacte r wat< r.
Re a < t. r w at e - conduc-rwo hours and twents tour minut es tivity immediately started to dec rease.
It.t er, reactor water conduc tivity was at 3.
mmhos and load was held at 252 *(e) while cleaning up water.
Four hours and forty six minutes later, reactor water conductivity had reduced to 1 mmho.
rhioride analysis of reactor water taken during t imes of ma dmun conduet t vi t y indicated 0.23 ppm, indicating that chloride levels were at a'l times wel: eithin the Technical Specification limit af 1 ppm.
Three hours and twenty minutes later. the control rod dr ve pump suction was returned to the condensate storage t ank which had dec reased in conduct i s it v from 25 mmhos to 5 hs <pil. ine to the main condense r ind recycling through an idle dimineralizer.
l Contamination of the condensate st 3 rage tanks occurred by a mal-function of equipment in the radiation waste facility. Water from the waste collector tanks passes through a filter and diminerati:cr. Conductivity is i
l determined by a cell at the dimineralizer discharge.
Water of st andard quality or above is pumped to the condensate storage tank through one of two flip-flop control valves.
The other valve opens when below standard water is produced, recirculating the effluent back ta the dimineralizer for addit ional purification.
The first valve of the pair is left closed during this process.
E d.[ fLf'{/
t 3992-chhjo Ko 1 4489
/-
COPY SENT REGION
o-
/"\\
\\
v/
U Page 2 On this occasion, the conductivity recorder stuck andjid not There fore,
permit the contact driven by the recorder mechanism to actuate.
below standa'f thratTr was seni to the condensate storage tanks, whic'h in
~
turn was pumped to the reactor by the control rod drive pumps.
A completely separate back-up system is presently being installed Another conductivity cell and switch (not depend-to prevent a recurrence.
ent on a recorder movement) are being connected in parallel with the present Either system (or both) will cause the proper valve action on high system.
conductivity.
Both systems will have the same switch point and failure of one system will not effect proper operation of the other.
Very truly yours,
' 9 l 5,lc m e j.
c.
F./ J. Schneider Vice President - Operations FJS:pw a..
\\_
/