05000346/LER-1980-057-03, /03L-0:on 800710,while de-energizing Sfas Channel 2 for Maint on Bus Y2,control Room Operator Received Decay Heat Loop 2 High Flow Alarm.Decay Heat Cooler 1-2 Discharge Control Valve DH14A Failed Open.Caused by Procedural Er

/03L-0:on 800710,while de-energizing Sfas Channel 2 for Maint on Bus Y2,control Room Operator Received Decay Heat Loop 2 High Flow Alarm.Decay Heat Cooler 1-2 Discharge Control Valve DH14A Failed Open.Caused by Procedural Error

ML19331B679
Person / Time
Site:	Davis Besse
Issue date:	08/07/1980
From:	David Brown TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19331B670	List: 05000346/LER-1980-057, Forwards LER 80-057/03L-0 05000346/LER-1980-057-03, /03L-0:on 800710,while de-energizing Sfas Channel 2 for Maint on Bus Y2,control Room Operator Received Decay Heat Loop 2 High Flow Alarm.Decay Heat Cooler 1-2 Discharge Control Valve DH14A Failed Open.Caused by Procedural Er
References
LER-80-057-03L, LER-80-57-3L, NUDOCS 8008120578
Download: ML19331B679 (3)

LER-1980-057, /03L-0:on 800710,while de-energizing Sfas Channel 2 for Maint on Bus Y2,control Room Operator Received Decay Heat Loop 2 High Flow Alarm.Decay Heat Cooler 1-2 Discharge Control Valve DH14A Failed Open.Caused by Procedural Error

Event date:
Report date:
3461980057R03 - NRC Website

text

=

U.S. NUCLEAR REGULATORY COMMISSION NT.C FoRf.1356 =

(7 77)

LICENSEE EVENT REPORT CONTROL BLOCK: l l

l l

l l

lh (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 1 6

\\l lo j t l l 0lH lD lB lS 11 l@l 0l 0l 0101010l 0l 0l Ol 0l Ol@l 4 l 1l 1l 1l 1l@l l

l@

7 8 9 LICENSEE CODE 14 lb LICENSE NUV8ER 2b 26 LICENSE TYPE JG Si CAT 3d CON'T fiTT1

,"g RC It l@l0 l 5 l0 l -l 0l 3l 4l 6l@l0 l 71 1l 0l 8l 0l@l l

l l

l l

l@

7 8

60 61 DOCKET NUVBER 68 63 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h o 2 l(NP-33-80-71) On 7/10/80 at 1639 hours0.019 days <br />0.455 hours <br />0.00271 weeks <br />6.236395e-4 months <br />, while deenergizing SFAS Channel 2. for I

g l maintenance on bus Y2, the control room operator received a Decay Heat Loop 2 high l

l o l 4 l l flow alarm.

It was discovered that DH Cooler 1-2 Discharge Control Valve DH14A had l

l o i s l {niled open.

SFAS Channel 2 was reenergized at 1050 hours0.0122 days <br />0.292 hours <br />0.00174 weeks <br />3.99525e-4 months <br />, however, DH14A began l

lo is 1 l closing.

DH14A Controller HIC DH14A overshot the previous setpoint and redu_ced decay l l heat to less than 2800 gpm.

There was no danger to the health and safety of the l

o 7 A flow of at least 2000 gpm was maintained.

i io gg i lpublic or unit personnel.

80 E

CODE S BC E COMPONENT CODE SU8 CODE 5

E to_LS]

IS IF l@ Laj@ L2J @ 171 z l z I z I z I z l@ Lz_J@ lz_J @

7 8

9 IO ft 12 33 18 19 20 SEQUENTIAL OCCURRENCE REPORT REVISION LER EVENT YE AR REPORT NO.

CoOE TYPE NO.

@ sgg/RO I810I L_J l o 1517 I l-l le 13 I Lt_. J l-l Lp_J a

_ 21 22 23 24 26 27 28 29 30 31 32 K N ACT ON PL NT ME HOURS S8 IT FOR1 8.

SUPPL 1 MAN FACTURER lXl@]Gl@

l Z l@

l2l@

[0_l0l0l0l [Y_j@

l l@

l Z l@

l Z l 9 l 9 l 9 l@

33 34 35 36 31 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS li l o l lThe cause was procedural inadeaucev. Oniv the AC oortion of SFAS Chnnnel 2 nonded to I i i Ibe deenergized. Decay heat flow was restored to creator chnn 7RM onm ne 1M1 hn. re I

ton 7/10/80 A temporary modification will be written to ensure that thn SFAS DC l

i 7 busses V1. Y?.

I l 1 l 3 l l Essential Instrument Power is not deenergized when takinc essential 1

! m lY3, and Y4 out of service.

I 7

8 9 A S

% POWER OTHER STATUS DIS O RY DISCOVERY DESCRIPTION UA l

lAl@l Control Room Indication l

J @ l0l0l0l@l l

t 5 A TiVITY CO TENT LOCATION OF RELEASE i

RELEASED OF RELE ASE AMOUNT OF ACTIVITY NA l

l l

[_zj @ [_Z_j@l i 6 80 7

8 9 10 11 44 45 PERSONNEL f MPOSURES NUMBER TYPE

DESCRIPTION

l

\\0l0l0]@lZl@]

NA l

i 7

,ERSONNEl',N;UJiES l '

OESCRiPTiON@

l t

NuveER l0l0l01@l NA i a 80 7

8 9 11 12 LCSS OF OR DAMAGE TO FACILITY r

l I

TYPE DESCRIP TION [zJ@lNA i o 80 7

8 9 _

10 ISSUE @ DESCRIPTION 8008120 67E i

i i i siiiiiiiiij7 l

l NA l

2 a 68 69 80 5 7

a 9 to L-W m 259-5000 Ext. 296 1

TOLEDO EDISON COMPANY DAVIS-BE'SSE NUCLEAR POWER STATION UNIT ONE

. SUPPLEMENTAL INFORMATION FOR LER NP-33-80-71 DATE OF EVENT: July 10, 1980 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Decay Heat flow rate less than 2800 gpm while in Mode 6.

Conditions Prior to Occurence: The unit was in Mode 6, with Power (MWT) = 0 and Load (Gross MRE) = 0.

D scription of Occurrence: At 1039 hours0.012 days <br />0.289 hours <br />0.00172 weeks <br />3.953395e-4 months <br /> on July 10, 1980, while de-energizing S3fety Features Actuation System (SFAS) Channel 2 in preparation for taking 120VAC c sential bus Y2 out of service for maintenance, the control room operator received a Decay Heat (DH) Loop 2 high flow alarm (flow greater than 3750 gpm.) Upon checking SEAS panel C5717 and assessing the operations activities being performed at the time of the incident, the operator discovered that Decay Heat Cooler 1-2 Discharge Control Valve DH14A had lost control power and had failed open, causing the high decay heat flow rate. Loss of control power to DH14A had occured when SFAS Channel 2 DC Essen-tial Instrument Breaker D2P19 was opened.

Operations re-energized SFAS Channel 2 at 1050 hours0.0122 days <br />0.292 hours <br />0.00174 weeks <br />3.99525e-4 months <br /> on July 10, 1980, and as a result, DH14A began closing in a attempt to control decay heat flow at its previous cetpoint of approximately 3000 gpm. DH14A controller HIC DH14A overshot the setpoint cnd reduced decay heat flow to less than 2800 gpm at 1050 hours0.0122 days <br />0.292 hours <br />0.00174 weeks <br />3.99525e-4 months <br /> on July 10, 1980.

The operator restored the decay heat flow to greater than 2800 gpm at 1051 hours0.0122 days <br />0.292 hours <br />0.00174 weeks <br />3.999055e-4 months <br /> en July 10, 1980.

Operation of Decay Heat Loop 2 at less than 2800 gpm placed the unit in action statement of Technical Specification 3.9.8 which states that, while in Mode 6, with less than one decay heat loop in service delivering greater than or equal to 2800 gpm,

Euspend all operations involvine an increase in decay heat load or a reduction in boron concentration of the Reactor Coolant System and close all containment penetra-tions providing direct access to the containment atmosphere within four hours.

Decay heat flow was less than 2800 gpm for 51 seconds and the minimum observed flow rate was approximately 2000 gpm.

Designation of Apparent Cause of Occurrence: This incident was caused by procedural crror. Instrument AC System Operations Procedure SP1107.09 required a full de-ener-l gization of SFAS Channel 2 when only the AC portion of SFAS Channel 2 needed to be de-energized in order to take Y2 out of service.

l Analysis of Occurrence: There was no danger to the health and safety of the public cr to unit personnel. No core alterations were in progress, containment integrity was already established, and a substantial decay flow rate (2000 gpm) was maintained throughout this incident.

l l

y TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE PAGE 2 SUPPLEMENTAL INFORMATION FOR LER NP-33-80-71 Cerrective Action: Upon discovery that the decay heat flow had decreased to less thtn 2800 gpm, the operator quickly restored the decay heat flow-rate to greater than 2800 gpm.

A temporary modification will be written for the Instrument AC System Procedure, SP1107.09 to ensure that the operator does not deenergize the SFAS DC Essential Instrument Power when taking 120 VAC Essential Busses Y1, Y2, Y3, or Y4 out of service. SFAS Procedure SP1105.03 is also being moded to provide guidance for partially de-energizing SFAS Cabinets.

Failure Data: There have been no previous similar events due to a procedural error.

/

9 k