05000265/LER-1986-001, :on 860103,at 97% Power,Group I Isolation & Subsequent Reactor Scram Occurred.Caused by Air Hose Breaking Loose & Striking Instrument Rack Due to Failure of Hose Connection

:on 860103,at 97% Power,Group I Isolation & Subsequent Reactor Scram Occurred.Caused by Air Hose Breaking Loose & Striking Instrument Rack Due to Failure of Hose Connection

ML20137Q543
Person / Time
Site:	Quad Cities
Issue date:	01/27/1986
From:	Hill K, Kalivianakis N COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF ADMINISTRATION (ADM)
References
LER-86-001, LER-86-1, NJK-86-23, NUDOCS 8602060298
Download: ML20137Q543 (4)

LER-1986-001, on 860103,at 97% Power,Group I Isolation & Subsequent Reactor Scram Occurred.Caused by Air Hose Breaking Loose & Striking Instrument Rack Due to Failure of Hose Connection

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) 10 CFR 50.73(a)(2)(1) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(x)
2651986001R00 - NRC Website

text

'

LICENSEE EVENT REPORT (LER)

Facility Name (1)

Dockat Number (2)

_Paoe (31 OUAD-CITIES. NUCLEAR POWER STATION. UNIT 2 01 51 01 01 of 21 61 5 1

of 0 3

Title (4) Unit 2 Reactor Scram Due to a Spurious Group I Isolation caused by air hose striking instrument rack.

Event Date (5)

LER NL W r (6)

Reoort Date (7)

Other Facilities Involved (At

,/,, Revision Month Day Year Facility Names l Qocket Numberf s1 Month Day Year Year

/// Sequential

//

,/pp Number

///

Number I

//

01 Sl 01 01 01 l 1 011 013 816 816

~~~

010 11

~~

010 011 217 816 01Sl010101 I l THIS REPORT IS SU8MITTED PURSUANT TO THE REQUIREMENTS OF 10CFR p

(Check one or more of the followinal fil) 20.402(b) 20.405(c)

_)L 50.73(a)(2)(iv)

73. 71( b)

POWER 20.405(a)(1)(1) 50.36(c)(1) 50.73(a)(2)(v) 73.71(c)

LEVEL 20.405(a)(1)(11) 50.36(c)(2) 50.73(a)(2)(vti)

Other (Spectfy (101 0

9 7

20.405(a)(1)(111) 50.73(a)(2)(1) 50.73(a)(2)(v111)(A) in Abstract below

_, 20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viti)(B) and in Text) 20.405(a)(1)(v) 50.73(a)(2)(111) 50.73(a)(2)(x)-

LICENSEE CONTACT FOR THIS LER (121 Name TELEPHONE NUMBER AREA CODE K. J. Hill. Technical Staff Enaineer Ext. 2150 310l9 61 51 41 -l 21 21 41 __

COMPLETE ONE LINE FOR EACH COMP FAILURE DESCRIBED IN THIS REPORT f13)

CAUSE

SYSTEMjCOMPONENT MANUFAC-REPORTABLE

CAUSE

SYSTEM COMPONENT MANUFAC-REPORTABLE TURER TO NPROS TURER TO NPRDS_

x L I F l l l l l 1 N

l I l l l l l 1

1 I I I I I I

I I I I I I SUPPLEMENTAL REPORT EXPECTED f14)

Expected Month ! Day l Year Submission lyes (If ves. complete EXPECTED SUBMISSION DATE)

X l No l

I I

ABSTRACT (Limit to 1400 spaces, i.e, approximately fifteen single-space typewritten lines) (16)

On January 3, 1986. Unit Two was operating in the RUN mode at 97% of rated thermal power. At 1425 hours0.0165 days <br />0.396 hours <br />0.00236 weeks <br />5.422125e-4 months <br /> a Group I Isolation occurred with a subsequent Reactor Scram. The isolation signal was generated spuriously when an air hose being used by contractor personnel broke loose from a Chicago fitting clamped to the hose, and struck an instrument rack. The root cause of the event was failure of the hose connection. Air hose connections have been and will continue to be inspected whenever a hose is returned to the tool room.

Additional corrective action to include investigating putting protective fences around the affected switches, and possible replacement of the switches with an analog type which are less susceptible to spurious trips of this type.

This report is submitted to you in accordance with the requirements of the Code of Federal Regulations, Title

10. Part 50.73(a)(2)(iv), which requires the reporting of any event that resulted in the actuation of any Engineered Safety Feature.

8602060298 060127 PDR ADOCK 05000265 S

pop

'j, ( V L

?

0380H

LICENSEE EVENT REPORT fLER) TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER f6)

Pace (3)

//,p/

Revision

,,/,

Sequential

//

Year p//

Number

/

///

Number Quad Cities Unit 2 015101010121*65 816 010l1 010 012 0F 013 TEXT

PLANT AND SYSTEM IDENTIFICATION

G1neral Electric - Boiling Water Reactor - 2S11 MWt rated core thermal power. Energy Industry Identification System (EIIS) codes are identified in the text as [XX].

IDENTIFICATION OF OCCURRENCE:

Air hose came detached and struck Main Steam Line Differential Pressure switches causing a Group I isolation which in turn caused a Reactor Scram.

Discovery Date:

01/03/86 RIport Date:

01/27/86 This report was initiated by Deviation Report D-4-2-86-01 CONDITIONS PRIOR TO OCCURRENCE:

Run Mode (4) - Rx Power 97% - Unit Load 800 MWe Run Mode (4) - In this position the reactor system pressure is at or above 825 psig, and the reactor prctection system is energized, with APRM protection and RBM interlocks in service (excluding the IS% high flux scram).

DESCRIPTION OF OCCURRENCE:

At 1425 hours0.0165 days <br />0.396 hours <br />0.00236 weeks <br />5.422125e-4 months <br />, on January 3, 1986, Unit Two Reactor received a Group I Isolation signal and subsequently scrammed due to the closure of the Main Steam Line Valves (MSIVs). The 902-S panel in the control room indicated that the isolation signal signal was caused by high main steam line flow. Unit Two was operating in the RUN mode at 97% of rated thermal power prior to the event.

This report is submitted to you in accordance with the requirements of the Code of Federal Regulations Title 10, Part 50.73(a)(2)(iv). which requires the reporting of any event that resulted in the actuation of any Engineered Safety Feature.

APPARENT CAUSE OF OCCURRENCE:

Th2 cause of the isolation and scram was failure of an air hose connection. An air hose broke loose from a Chicago fitting attached to the hose, and struck instrument rack 2202-10 causing a spurious Group I isolation signal. Two contractor personnel were preparing to clean welds for Nutech Hanger M-1806-21 in the south Residual Heat Removal Systen (RHR)[B0] room. To clean the welds the two used an air-powered grinder which was connected to service. air with 3/4 inch standard air hose and Chicago Fittings. One contractor noticed a safety pin (there are two required) was missing between the Chicago fittings. As he was installing the

'0380H

D LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER f6)

Pace (3)

Year

///

Sequential /,/

Revision

/

pp,

///

Number

///

Number Quad Cities Unit 2 0l 5 1 0 1 0 1 0 1 21 *6 5 816 010l 1 0 IO 013 0F 013 TEXT missing safety pin, the other contractor picked up the grinder in preparation to clean the weld. At this time the Chicago fitting came out of the hose. The Chicago fitting was a standard barbed er.:1 type and was clamped to the hose by a worm-drive type clamp. The hose had been in use earlier that morning and during the previous day. The loose end of the hose, still under pressure, began thrashing violently, striking instrument rack 2202-10 several times. The C and D Main steam lines each have 4 differential pressure switches (DPIS 2-261-2) located on this rack. The contacts of the switches are wired in a ont-out-of-two-twice logic arrangement to give a Goup I Isolation on high steam line flow. Spurious activation of one of these switches on each division would have caused the isolation signal.

ANALYSIS OF DEVIATION:

Tha MSIVs close on a Group I Isolation signal. MSIV closure initiates a Reactor Scram signal, when operating in the RUN mode, when the isolation valves reach 10% closed from the full open position. This scram anticipates the pressure and flux transients which would occur when the valves fully closed. All systems functioned as designed upon initiation of the isolation signal. Operator action was to control reactor water level and reopen the MSIVs to control reactor pressure. Proper equipment operation and prompt operator action minimized the consequences of this event. The affected instruments were inspected by the Instrument Maintenance Department and found to be undamaged.

CORRECTIVE ACTION

The station will continue to inspect all air hose connections whenever a nose is returned to the tool room.

Action Item Record (AIR) 86-04 has been initiated to investigate replacing the presently installed differential pressure switches with analog devices, which are less susceptible to the spurious trips of this type. The current switches are renuf actured by Barton, model No. 278.

In the interim, the station Technical Staff will investigate placing barriers around the racks. Installation of barriers will be contingent upon obtaining a design which addresses seismic concerns and physical space limitations. The eventual replacement of the Barton switches with analog devices will prevent recurrences of this type.

FAILURE Thsre have been several occasions in the past where inadvertent contact with instrument racks has caused a Reactor Scram. The most recent occurrence was on February 16, 1983. when a spurious high steam line flow signal caused a Group I isolation and scram. This incident is recorded in DVR 4-1-83-16.

0380H t

Commonwealth Edison ouad Cities Nuclear Power Station 22710 206 Avenue North Cordova. Il!!nois 61242 Telephone 309/654-2241 NJK-86-23 January 28, 1986 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Reference: Quad-Cities Nuclear Power Station Docket Number 50-265, DPR-30, Unit Two Enclosed please find Licensee Event Report (LER) 86-01, Revision 00, for Quad-Cities Nuclear Power Station.

This report is submitted to you in accordance with the requirements of the Code of Federal Regulations, Title 10, Part 50.73(a)(2)(iv), which requires the reporting of any event that resulted in the actuation of any Engineered Safety Feature.

Respectfully, COMMONWEALTH EDISON COMPANY QUAD-CITIES NUCLEAR POWER ST TION

/ 0 Y "4,Y N. J. Kallvianakis Station Manager NJK/MSK/dak Enclosure cc: J. Hojnarowski A. Madison INPO Records Center NRC Region III y,

n,N