05000263/LER-1987-001, :on 870108,reactor Pressure Sys Actuation, Primary Containment Groups II & III Isolation & Standby Gas Treatment Sys Initiation Occurred Due to Reactor Low Water Level.Caused by Operator Error.Esf Sys Reset
| ML20207Q446 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 01/19/1987 |
| From: | Antony D, Musolf D NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF ADMINISTRATION (ADM) |
| References | |
| LER-87-001, LER-87-1, NUDOCS 8701270338 | |
| Download: ML20207Q446 (3) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(x) |
| 2631987001R00 - NRC Website | |
text
,
.[
~lNRC Form 366 U.S. NUCLEAR REGULATORY COMMISSION l
- - l(9-83)
Approved OMB NO. 3150-0104 l
l.
LICENSEE EVENT REPORT (LER)
Expires 8/31/85 l
l 1
- - l FACILITY NAME (1) l DOCKET NUMBER (2) 1 PAGE (3) l l
Monticello 10 l5 10 l0 10 1 2l 61 311 l OF l Ol 2l l TITLE'(4) l l
ESF Actuation Due to Low Reactor Water Level l
lEVENT DATE (5)l LER NUMBER (6) l REPORT DATE (7)l OTHER FACILITIES INVOLVED (8)l lMONTHIDAYl YEAR l YEAR l l SEQUENTIAL l lREVISIONIMONTHlDAY l YEAR l FACILITY NAMES l DOCKET NUMBERS l.
1-l l
l l l NUMBER l l NUMBER I l
l l
10151010l01 l l l l-1 I
l l l l l 1
l l
l l
l l 01 1l0l8l 8171 8171-1 Ol 0 l 1 l-l 0 l 0 l of Il 1l91 817l 10151010101 l 1l l OPERATING l ITHIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS l
l MODE (9) lNIOF 10 CFR 6:
(Check one or more of the followina)(Il) l lPOWERl M 20.402(b)
M 20.405(c)
IXl 50.73(a)(2)(iv) l l 73.71(b)l lLEVELI l l M 20.405(a)(1)(1) l l 50.38(c)(1) l l 50.73(a)(2)(v)
M 73.71(c)l l (10)l0101 01 l 20.405(a)(1)(ii) M 50.36(c)(2) l l 50.73(a)(2)(vii)
M OTHER I
I l l 20.405(a)(1)(iii) M 50.73(a)(2)(i) l l 50.73(a)(2)(viii)(A) (Specify ini
- - l l l 20.405(a)(1)(iv) M 50.73(a)(2)(ii) M 50.73(a)(2)(viii)(B) Abstract l
l.
M 20.405(a)(1)(v)
M 50.73(a)(2)(iii) M 50.73(a)(2)(x) below and l
l in Text. NRC Form 366A)l l
LICENSEE CONTACT FOR THIS LER (12) l lNAME l
TELEPHONE NUMBER l
l l AREA CODE l l
1
- - Doualas D. Antony, General Superintendent, Operations l 61 Il 2 l 21 91 51-151115l11 l
COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) l l
I l
lMANUFACl REPORTABLE l l
l l
lMANUFAClREPORTABLEl l
lCAUSElSYSTEMICOMPONENTl'TURER l TO NPRDS l lCAUSElSYSTEMl COMPONENT l TURER l TO NPRDS l l
l 1
l l
l l
l 1
l I
l l
l l
l 1
l l l 1ll l l l l
l l
l l
l l l l l l l l l
l l
I l
1 l
l l
l l
l l
l l
l l
l l
l l l l l l l l l
l l
l l
l l l l l 1Il l
l
- - l SUPPLEMENTAL REPORT EXPECTED (14) lEXPECTED l MONTH l DAY lYEARl l
l l SUBMISSION l l
l l
l LYES (If yes, complete EXPECTED SUBMISSION DATE) l XlNO l DATE (15) l l
l l l l l l ABSTRACT (Limit to 1400 spaces, i.e.,
approximately fifteen single-space typwritten lines)l l
(16) l l
While establishing a cooldown rate during a normal plant shutdown, a reactor l
l protection system actuation, a primary containment group II and III isolation l
l l
and a standby gas treatment system initiation occurred due to a reactor low l
l water level condition. All control rods were fully inserted at the time of the l
l event. The reactor level control system was in the manual mode at the time of the l
l event.
The cooldown rate was established by bypassing steam to the main condenser.
l l
The reactor operator did not take timely action in response to the level decrease l
l as a result of the cooldown to prevent the low level condition.
Licensed operators l
l were reminded to provide dedicated surveillance of reactor level when operating in l
l the manual mode of reactor level control.
l l
l l
1 l
1 Mb
[
8 I
l I
I I
l NRC Form 366 t
(9-83)
I,E 22 DJJ442
'f l
48 lNRC F rm 365 U.S. NUCLEAR REGULATORY COMMISSION l
- - l(9-83)
Approved OMB NO. 3150-0104 l
l LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Expires 8/31/85 l
l l
l FACILITY NAME (1) l DOCKET NUMBER (2) l LER NUMBER (6) l PAGE (3) l l
l l YEAR l l SEQUENTIAL l l REVISION l l
l l
l l
l l l NUMBER l l NUMBER l
l l
l l Monticello l0l5l0l0l0l 2l 61 3l 8l7l-l Ol 0l 1l-l 0 l 0 l0l2lOFl0 l2l l TEXT (If more space is required, use additional NRC Form 366A's) (17) l 1
l l
On January 8, 1987, at 1854 hours0.0215 days <br />0.515 hours <br />0.00307 weeks <br />7.05447e-4 months <br />, during a normal plant shutdown for a scheduled l
l maintenance outage, a reactor protection system (JC) actuation, a primary containment l l
group II/III isolation (JM), a secondary containment isolation, and a standby gas l
l treatment system (BH) initiation occurred due to a reactor low water level condition. l l
All control rods were fully inserted at the time of the occurrence. Reactor pressure l l
was approximately 600 psig.
The reactor level control system (JB) was in the manual l
l mode and reactor level was being maintained below the low level alarm setpoint l
l prior to the occurrence. The reactor operator was deliberately controlling the l
l level low to avoid a high water level trip from the protection system instruments l
l which sense level independent of the level control system instruments (as the reactor l l
is cooled down, a disparity between the level control instrument indications and the l
l trip system instrument indications occurs due to water density effects and the l
l differences in compensation for these effects). The reactor pressure was being l
l maintained at approximately 600 psig prior to the occurrence to accommodate an l
l inspection of the primary system for leaks inside the drywell. When the inspection l
l was completed, a cooldown rate was established on the reactor by bypassing steam l
l to the main condenser. This resulted in a level loss from the reactor. The reactor l l
operator did not take timely action in response to the level decrease to prevent l
l the low level condition. The cause of this event is a cognitive error by a licensed l l
operator. The error was not the result of actions contrary to an approved l
l procedure.
l l
l l
All appropriate automatic actuations in response to the low level condition occurred. l l
All systems functioned properly. The ESF actuations were annuniciated in the l
l control room.
The error was immediately recognized and proper reactor level was l
l restored. All ESF systems were immediately reset. There were no unusual l
l characteristics of the work location that directly contributed to the error.
l l
Licensed operators were reminded to provide dedicated surveillance of reactor water l
l level when operating in the manual mode of reactor level control.
l l
l l
No previous similar reportable events.
No effect on public health and safety as this l l
was an inadvertent ESF actuation and all systems functioned properly. There are no l
l other conditions that would have resulted in more severe health and safety l
l consequences had the event occurred under thost conditions.
l l
l l
l l
l l
l l
l l
l l
1 l
1 l
l l
1 l
l l
l(9-83)
DJJ442
r W
Northern States Power Company 414 Nicollet Mall Minneapoks. Minnesota 55401 Telephone (612) 330-5500 January 19, 1987 Report Required by 10 CFR Part 50, Section 50.73 U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 ESF Actuation Due To Low Reactor Water Level The License Event Report for this occurrence is attached.
This event was reported via the Emergency Notification System in accordance with 10 CFR Part 50, Section 50.72, on January 8, 1987.
YlGu'()
. David Musolf Manager - Nuclear Support Services DMM/MMV/ dab c: Regional Administrator-III, NRC NRR Project Manager, NRC Resident Inspector, NRC MPCA Attn: J W Ferman Attachment S' )
/