05000266/LER-1985-001, :on 850405,during Refueling Shutdown W/Plant Proceeding Toward Cold Shutdown,Pressure on Steam Line a Decreased Causing Actuation of Safety Injection.Caused by Inadequate Precautions in Procedure OP-3C
| ML20127K147 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 05/03/1985 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| LER-85-001, LER-85-1, NUDOCS 8505220055 | |
| Download: ML20127K147 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv), System Actuation |
| 2661985001R00 - NRC Website | |
text
C
,6 NaC Per'as me U.S. NUCLEAD REGULATORY -
AprROVED Oese eso. 31904104 UCENSEE EVENT REPORT (LER) 8 ""' 8 **
PACIL87V IIARIE H) 1 o l5 l o lo Io l2 l6 l6 1 loFl ol 3 DOCNET NUSWen W Pass (3 Point Beach Unit TITLE le Inadvertent Safety Injection Actuation on Low Steam Line Pressure Eves (T DATE (el LER seusseER 461 REPORT DATE (7)
OTHER PACILITIEe 18ev0LVILD WI 88,0
[,"b M0'eTM DAY VEAR PaciLITY maues DOCKET seUaseERis)
MONTH DAY VEAR YEAR v5 0Islogolog i l 0 l4 0l5 85 8l 5 0l 0l 1 0l0 0 l5 0l3 8l 5 oisio soio, i ;
Twis REPORT is eueMiTTED PvReuANT To Tm REauinensENT or to CrR g: ten. *.
.a n sww Hu "888
- N as esEM se.4eme y
esmmw Tusw O00 as sewm:n es.mwm suswmw ruu.i i i m sewmm es.mwm sumime.c gRg,,.y, n
qg w sewmtmi euswmin suswmi nAs msAs c
M' amwmiw mmmm u m an.n.
3 fisi:
as.esswmM es.734 alt 2)til0 m.73Eenanal LBCENsEE C088 TACT POR THIS LER H2)
N^ME TELEPHONE NUMeER
^"'^c"'
C. W.
Fay, Vice President-Nuclear Power 2 7;7 i 2;8;l 1 4l1 4 1
1 i
1 COedPLETE 08st LifsE FOR EACH CORAPO90ENT FAILURE DEeCRaeED IN THe8 REPORT H3 [g'
CAUSE
SYSTEM COMPONENT I"
, y[i
CAUSE
SYSTEM COMPONENT g
TU E l
i I I I i 1 I
, I l l l 1
I l l l l l l
l l l l l 1 v
eUPPLEa0 ENTAL REPORT EXPECTED He MONTH DAY VEAR sutMIS$ ION YE$ lor y.e, e.n%N se EXPECTED SV0nat$$,0N DA TEl NO l
l l
AesTRACTtv we = e m a.
swr==.,.
.r -,
,um On April 5, 1985, during a scheduled refueling plant shutdown, low steam' pressure caused an actuation of safety injection.
The reactor was subcritical and in hot shutdown when the actuation occurred.
No flow into the reactor coolant system occurred due to reactor coolant sy' stem pressure above the shutoff head of the safety injection pumps.
All systems performed as expected during the safety in3ection actuation.
The primary cause of this actuation was inadequate precautions'in pro-cedure OP-3C, " Hot Shutdown to Cold Shutdown," which is used for this evolution.
8505220055 050503 ADOCK 050 g 6 PDR 9
=--
r asnC Foren 3BSA U.S. NUCLElid 3.EIULATORY COMMISSION M
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION AreROvso Ous =0. siso-cio.
=
exemas sauss FACILITY MAME Of DOCKET NUMBER (2)
LER NUMSER (5) eAGE (3)
VEAR SE QUE NTI A L REV 8sOh Point Beach Unit 1 o ls lo lo jo l2 l6 l6 8l5 0l0l1 0l 0 0l 2 0F 0 13 ruxT n
=== =.
wmc r issa nn During an April 5, 1985, scheduled refueling shutdown of Point Beach Nuclear Plant, Unit 1, with the plant proceeding toward cold shutdown, steam line pressure on the "A"
steam line decreased to less than the actuation setpoint causing the actuation of safety injection at 1413 hours0.0164 days <br />0.393 hours <br />0.00234 weeks <br />5.376465e-4 months <br />.
Since the reactor was already shut down, the only actual actuation was the safety injection system.
The reactor coolant system pressure was at 1985 psia at the time of the safety injection actuation.
Therefore, there was no actual injection of water into the reactor coolant ~ system.
All systems associated with the actuation of safety injection operated in a normal manner.
At the time of the actuation, the operators were attempting to main-tain the primary system at 520 degrees Fahrenheit.
This temperature was being maintained to make it possible to soak the steam generators for chemistry sampling of the secondary side of the steam generators.
During this cooldown, nonroutine temperature hold points for steam generator sampling were requested by Chemistry.
A number of steam generator low pressure alarms occurred while the Control Operator was involved in numerous cooldown evolutions.
The low pressure alarms and their possible safety injection impact were discussed briefly be-tween the operators.
The primary system had been at 520 degrees Fahrenheit and a cooldown to 420 degrees Fahrenheit was about to start.
The temperature was to be held at 420 degrees Fahrenheit for another sampling sequence of the steam generator inventory.
During the reduc-tion in primary temperature, the computer alarms and channel alerts for the safety injection actuation occurred along with other alarms in that period just prior to the actuation.
The. Duty Shift Supcrin-tendent and Duty Operating Supervisor beli'eved'that the Control Operator had the primary and secondary systems under control and, therefore, returned to the rest of the work being done in the plant to reach cold shutdown conditions.
Pressurizer pressure control was in auto-matic with heaters on for recirculation of the pressurizer volume.
The steam dump controller was set in automatic pressure control and was lowered slightly during the beginning of the cooldown from 520 degrees Fahrenheit to 420 degrees Fahrenheit.
Although steam pressure was under automatic control, the reduction in the secondary system pressure caused a drop in steam generator level which was countered by automatic level control.
This level control introduced a quantity of cold water into the steam generator.
These evolutions reduced. steam line pressure below the safety injection setpoint.
After the safety' injection signal, it was verified that appropriate actuation'had' occurred and both pumps had started. There was no injection because the primary pressure was above the pump shutoff head.
Primary and secondary pressures and temperatures were stabilized, safety injection was reset, and the cooldown was resumed.
g
.M -.
w IIRC Form 3004 U.S. NUCLEAR KEIULi. TORY COMMISSIO8d F"
LICENSEE EVENT REPORT (LER) TEXT CONTINUATION AreaovEo oMe Ro. aiso-oio.
EXPIRES 8/31/85 PACIUTY NAA8E (U DOCKET NUa85ER 12)
LER NUMSER 88)
PAGE(30 Point Beach Unit 1 0l5l0l010l21616 815 0 l 011 01 0 01 3 OF 0 13 TEXT n A
=
Mwme r msaw nn OP-3C, " Hot Shutdown to Cold Shutdown," is the procedure used to per-form the operations described above.
Although the procedure has many precautions and limitations which discuss various concerns about the cooldown, the procedure does not discuss the stepped temperature holds used during this cooldown and the impact that the cooldown technique might have on the timing for the blocking of safety injection.
The procedure in fact has a possible branch to an addendum at the point the safety injection occurred which provides for a bypass of the low-low steam pressure safety injection signal.
The next page of the procedure provides for the manual block of the safety injection signal due to primary pressure.
The reduction of steam line pressure and its impact on the possible safety injection is not discussed in this part of the procedure.
Review of the procedure has taken place and changes to the procedure for plant cooldown are being developed to clarify and better control the portion of the procedure used for blocking of safety injection.
We expect completion of review and approval to be completed by July 1, 1985.
Additionally, the operators involved'have been advised to assure appropriate oversight and control of the unit during all phases of operation and especially during transients between modes of operation.
The Senior Resident Inspector has been notified of this event.
l ll
,.g..u. a.
. o..
d
..4 IRSCOnSin Electnc ma comy
- 231 W. MICHIGAN, P.O. BOX 2046. MILWAUKEE, WI 53201 May'3, 1985
.Mr.
J.'G.
Keppler, Regional Administrator Office of Inspection and Enforcement, Region III
.U.
S. NUCLEAR REGULATORY COMMISSION 799 Roosevelt Road Glen Ellyn, Illinois -60137
Dear Mr. Keppler:
DOCKET NO. 50-266 LICENSEE. EVENT REPORT NO. 85-001-00 INADVERTENT SAFETY INJECTION. ACTUATION ON LOW STEAM LINE.' PRESSURE.
POINT BEACH NUCLEAR PLANT, UNIT 1 Enclosed is Licensee Event Report No. 85-001-00 for
. Point Beach Nuclear Plant, Unit 1, which provides a description of an inadvertent actuation'of safety injection initiated by low steam line pressure while in a shut down condition.
This is reportable ~ in accordance with 10 CFR 50.73 (a) (2) (iv), "Any event or condition that resulted in manual or automatic initiation of any engineered safety feature, including the reactor protection system."
Very truly yours, 7
Vice President-Nuclear Power C..W.-Fay Enclosure Copy to NRC Resident Inspector NAY 91985
....#y m