ML20059C990

Intervenor Exhibit I-MFP-126,consisting of 911030, DC2-91-TI-N088 D2, Inadvertent SI Due to Personnel Error

ML20059C990
Person / Time
Site:	Diablo Canyon
Issue date:	08/21/1993
From:	AFFILIATION NOT ASSIGNED
To:
References
OLA-2-I-MFP-126, NUDOCS 9401060301
Download: ML20059C990 (11)

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I-/#F#-/2/o ~obisi-T1-N08802 October 30, 1991

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l INADVERTENT SI DUE TO PERSONNEL ERROR

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SUMMARY

, On October 6, 1991 at 0008 PDT with Unit 2 in Mode 5, two l Instrument and Controls technicians were reconfiguring the

! Solid State Protection System per STP I-16D4. In violation of the procedure both technicians incorrectly placed the '

outputs in operate prior to inhibiting the. inputs resulting in a safety injection signal'from each SSPS train and.an-inadvertent safety injection.

Root Cause:

Personnel error, in that the technicians did not utilize the applicable procedure when performing the SSPS realignment.

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9-Mt DC2-91-TI-N08- 02 October 30, 1991 INADVERTENT SI DUE TO PERSONNEL ERROR

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I. Plant Conditions Unit 2 was in Mode 5-(2R4 Refueling Outage).

II. Description of Event A. Event:

On October 5, 1991, two Instrument and Controls (I&C) technicians were. assigned work order R0088409 to reconfigure t.he SOLID STATE PROTECTION SYSTEM (SSPS) from "INPUf8 IN NORMAL / OUTPUTS IN TEST" to " INPUTS INHIBI".'ED/ OUTPUTS IN OPERATE" per Surveillance Test Procedtre (STP) I-16D4, "Reconfiguring an SSPS Trcin in Modes 5 or 6," by the cognizant I&C foreman, Since the SSPS.was removed from service and both' technicians had previously been tailboarded and had successfully performed the same STP earlier!in the' week no additional tailboard was conducted. The.

technicians were informed there'was no rush to complete this job.

The 'two technicians then' proceeded: to the control Room and obtained permission from the' Shift Foreman (SFM) and Control. Operator (CO) to-reconfigure SSPS Trains A and:B.

On October 6, 1991, at 0008:29.426 PDT the "SSPS GENERAL WARNING TRAIN-B" alarm occurred when one j l technician repositioned the Train B " MODE i SELECTOR" switch to the " OPERATE" position prior

! to placing the " INPUT ERROR INHIBIT" switch in the

! " INHIBIT" position. This sequence is opposite the required sequence of STP I-16D4. The' technician did not have a copy of STP I-16D4 in his possession when manipulating the switches. The l

repositioning of this switch' created a' safety injection (SI) signal. The second technician was proceeding to SSPS train A and was not present when the first technician reconfigured train B of the SSPS. This placed SSPS train B " OUTPUTS IN OPERATE" and " INPUTS IN NORMAL"'and the following-actions occurred:

91NCRWP\91 TIN 088.JCN 'Page 2 of 11

e YJ DC2-91-TI-N088 D2 October 30, 1991 CONTAINMENT ISOLATION PHASE A, 4KV BUS-G AUTO XFR, 4KV BUS-H AUTO XFR, FW ISOL FROM REACT TRIP'P-4 AND LO Ta va 2/4, DSL 2-2 CRANKING, AUX SALT WTR PP 2-1 and SAFETY INJECTION.

On October 6, 1991 at 0008:30.596 PDT~an "SSPS GENERAL WARNING TRAIN-B" alarm occurred when the technician placed the Train B " INPUT-ERROR INHIBIT" switch in the " INHIBIT" position, this placed SSPS train "B" in the intended configuration per STP I-16D4.

On' October 6,.1991 at 0008:56.345 PDT the "SSPS GENERAL WARNING TRAL'N-A" alarm occurred when 'the second technician, acting independent of the first technician, placed the SSPS Train A "MODELSELECTOR SWITCH" in the " OPERATE" position prior to placing the " INPUT ERROR INHIBIT" switch in the " INHIBIT" position. This switch repositioning created a second SI signal. The technician did have a' copy of STP I-16D4 with him at the time but was referring to the " Summary Sheet" instead of the procedure. This placed SSPS Train A " OUTPUTS IN OPERATE" and " INPUTS IN NORMAL" and the following l actions occurred:

4KV BUS-F AUTO XFR, DSL 1-3 CRANKING and l MAIN STM ISOLATED.

On October 6, 1991 at 0009:00.149- PDT an "SSPS GENERAL WARNING TRAIN-A" alarm occurred when the second tcchnician placed the Train A " INPUT ERROR INHIBIT" switch in the " INHIBIT" position, this placed SSPS Train A in the intended configuration per STP I-16D4.

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DC2-91-TI-N088 D2 .

October 30, 1991 3

The two technicians then verified Lthat'each' train was properly configured per-STP I-16D4 and.- ,

initialled the summary sheet.- . Upon. entering the  !

Control Room.the technicians were informed by-  !

Operations that "...something had gone i wrong." The technician who had'reconfigured SSPS l Train'A retraced his steps and realized'he hadl operated the switches in1the incorrect order and l

informed his. supervisor.

i On October 6, 1991,-at 0015 PDT,-Operations-l personnel reset the SI and returned the plant"to l normal Mode 5 alignments.

1 i B. Inoperable Structures, Components, or Systems that' Contributed to the Event: 3 None. '

C. Dates and Approximate Timesffor Major Occurrences:

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1. Oct. 6, 1991; 0008:29 PDT:- Event / discovery '

date. An-SSPS.  ;

Train ~B.SI signal-

-.o C C u r s .

2. Oct. 6, 1991; 0008':56 PDT:- Event date.- An l SSPS Train A-SI

. signal' occurs.. [

( 3. Oct. 6, 1991; 0015 PDT: All L equipment;and valves returned to i normal ~ Mode 5' alignments . : i

4. Oct. 6, 1991;.0218 PDT:. A four-hour- '

non-emergency report required by' )

10 CPR 50.72~ J (b) (2) (ii) was I made. I D. Other Systems or Secondary Functions Affected Auxiliary Salt Water Pump:2-1. Auto-Start, Residual Heat Removal Pump 2-1. Auto-Start, 91NCRWP\91 TIN 088.JCN Page 4 of 11 i i p

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I i DC2-91-TI-N088 D2 i October 30, 1991

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l Diesel Generators 1-3 and 2-2 Auto-Start and Vital 4KV Busses F, G and H Auto-Transfer.

l l E. Method of Discovery:

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The event was immediately apparent to plant I operators due to alarms and indications received i in the Control Room.

l F. Operators Actions:

Operations personnel reset the SI and returned all equipment and valves to a normal Mode 5 alignments.

G. Safety System Responses:

The following Engineered Safeguards Actuations ,

occurred:

l Safety injection, l

l Vital 4kV busses transferred to Startup power, Phase "A" Containment Isolation, Feedwater Isolation, Main Steam Line Isolation and Diesel Generators started.

III. Cause of the Event  ;

l A. Immediate Cause:

The immediate cause of the event was improperly configuring of the SSPS inputs in " Normal" /

outputs in " Operate" while in Mode 5 operation.

l B. Determination of Cause I

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1. Human Factors: I

a. Communications:

l Communication was inadequate in this event 91NCRWP\91 TIN 088.JCN Page 5 of 11

DC2-91-TI-N0*" 02 October 30, 1991 in that the tailboard did not re-emphasize the risks and requi* .ents associated with reconfiguring the J.ed. The technicians acted independently and failed to utilize i concurrent verification when manipulating equipment that could result in an ESF actuation. i l

b. Procedures:

STP I-16D4 is adequate as written and l contains the proper sequencing to prevent l this occurrence, and also requires the use of concurrent verification. The technicians failed to utilize the procedure.

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c. Train 2ng:

STP I-16D4 does not remove the SSPS from service or return the SSPS to service and, in fact, is only performed when the SSPS is removed from service, therefore, no 1 specific qualification exists for performance of this procedure. However, since both technicians had successfully performed STP I-16D4 in the very recent i past, the I&C foreman felt that the l technicians were qualified to perform this i task. The senior technician was qualified to perform STP I-16D4.

d. Human Factors:

No human factors were relevant to this event.

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e. Management System: i Management has issued numerous procedures, l policies and tailboards emphasizing verbatim compliance, self-verification and concurrent verification. The technicians were aware of these procedures and policies but failed to follow them. The PG&E Positive Discipline Program has been in effect'since January 1991 and has shown improvement in these areas.

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DC2-91-TI-N088<D2

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2. Equipment / Material:-  ;

a. Material Degradation: N/A.

'b. Design: N/A.

c. Installation: N/A.

d. Manufacturing: N/A.

e. Preventive Maintenance: N/A..

f. Testing: N/A.

g. End-of-life failure: 'N/A.

C. Root Cause:

Root cause of.the event is personnel error, in that technicians did not utilize.the applicable procedure during performance'of STP I-16D4.

D. Contributory Cause:

1. The technicians did not practice-self-  ;

verification.

2. The technicians did not practice: concurrent verification.

IV. Analysis of the Event A. Safety Analysis:

Unit 2 was in Mode 5 when this' event occurred.

The accident-mitigating, Engineered Safety. Feature (ESP) equipment functioned as. intended.. SI actuated, 4kV vital busses ~ transferred to Startup power, a Phase A containment isolation occurred, Feedwater isolated, Main Steam: isolated,.ASW pump.

2-1 started, RHR pump.2-2 and DGs.1-3 and 2 started.

I No water was injected into the RCS'since ECCS pumps were secured ~for. refueling outage maintenance.

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DC2-91-TI-N088 D2 l October 30, 1991

Thus the health and safety of the public were not adversely affected by this event.

B. Reportability:

1. Reviewed under QAP-15.B and determined to be non-conforming in accordance with Section 2.1.2.

2. Reviewed under 10 CFR 50.72 and 10.CFR 50.73 per NUREG 1022 and determined to be reportable l in accordance with 10 CFR 50.72 (b) (2) (ii) 'and

' 10 CFR 50.73 (a) (2) (iv) as an ESF actuation.

See Licensee Event Report (LER) 2-91-007 for more information.

3. This event does not require a 10 CFR 21 l report.

4. This event does not require reporting via an INPO Nuclear Network entry.

5. Reviewed 10 CFR 50.9 and determined the event-was not reportable under 10 CFR 50.9 since event was being reported under 10 CFR 50.73.

6. Reviewed under the criteria of AP C-22 requiring the issue and approval of a JCO and determined that no JCO is required.

V. Corrective Actions A. Immediate Corrective Actions:

After determining the cause of the event was  !

personnel error, Operations returned the plant to l normal Mode 5 alignments.

B. Corrective Actions to Prevent Recurrence:

1. An I&C Department tailboard was held on October 7, 1991 by the I&C Section Director i and General Foremen, again emphasizing the importance of verbatim compliance, self-verification and concurrent verification.

RESPONSIBILITY: W. Crockett COMPLETE I&C (PSIT) 91NCRWP\91 TIN 088.JCN Page 8 of 11

s DC2-91-TI-N088 D2 October 30, 1991 AR A0246850, AE # 01 Not outage related.

No JCO required.

Not an NRC commitment.

Not a CMD commitment.

2. A memorandum will be issued by the Vice President for DCPP Operations emphasizing the necessity to utilize procedures, self-verify and concurrent verify when working with equipment that affects personnel and Plant safety.

RESPONSIBILITY: W. Crockett COMPLETE I&C (PSIT)

AR A0246850, AE # 02 Not outage related.

No JCO required.

Not an NRC commitment.

Not a CMD commitment.

3. The foreman and technicians responsible for this event will be counselled in accordance with the PG&E Positive Discipline Program.

RESPONSIBILITY: W. Crockett COMPLETE I&C (PSIT)

AR A0246850, AE # 03 Not outage related.

No JCO required.

Not an NRC commitment.

Not a CMD commitment.

VI. Additional Information A. Failed Components:

None.

B. Previous Similar Events.

Licensee Event Report 1-84-008, " Inadvertent  :

Safety Injection Actuation," dated April 16, 1984, I describes a similar event. An I&C technician was performing STP I-16B, " Testing of Safety Injection Reset Timer and Slave Relay K602," when he j deviated from the STP and placed the " INPUT-ERROR- '

INHIBIT" switch for Train A into the " NORMAL" 91NCRWP\91 TIN 088.JCN Page 9 of 11

I DC2-91-TI-N0"" D2 October 30, 1991 position, causing an SI. The technician was l

counselled and other I&C personnel were briefed on

the need to follow procedures and inform l supervision when unexpected test results occur.

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The corrective actions for LER 1-84-008 could not i have prevented the event reported in NCR DC2 TI-N088 since the personnel involved in the 1991 event made a consciou- decision not to utilize the STP.

C. Operating Experience Review:

1. NPRDS: )

i Not applicable.

2. NRC Information Notices, Bulletins, Generic l

Letters:  ;

None.

3. INPO SOERs and SERs:

None.

D. Trend Code:

TI (I&C) - A1 (personnel error, procedure not followed).

E. Corrective Action Tracking:

1. The tracking action request is A0246850.

2. Corrective actions are not outage related.

F. Footnotes and Special Comments:

None.

G.

References:

1. Initiating Action Request A0246453,

2. LER 2-91-007.

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DC2-91-TI-N088 D2 l October 30,-1991 l i

H. TRG Meeting Minutes: i J

On October 9, .1991, at 1:00 pm PDT in Room :533 of  !

the Administration Building,.the TRG held the initial meeting regarding the-SI that occurred-in Unit 2 on October 6, 1991. .The SI.was due to ,

personnel error, when;two I&c. technicians 1 independently caused-an SI signal in each of the l two trains of SSPS due to not utilizing the l applicable STP. j There was no hardware, software or procedural problems involved in this event. There was, however, a personnel safety near-miss. A-worker.

was working on an MSIV when-the inadvertent sis ,

occurred and had to jump back to avoid the closing valve. Fortunately, his injuries were minor. See ,

AR A0247268 for more information. -

No reconvene is. planned for this TRG. The estimated closure date for this NCR11s January-31,-

1992.

I. Remarks:

None, t

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