ML20059C998

Intervenor Exhibit I-MFP-127,consisting of LER 2-91-007-00, Re Docket 50-323,dtd 911101

ML20059C998
Person / Time
Site:	Diablo Canyon
Issue date:	08/21/1993
From:	Rueger G PACIFIC GAS & ELECTRIC CO.
To:
References
OLA-2-I-MFP-127, NUDOCS 9401060306
Download: ML20059C998 (6)

Text

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• Pacific Cas and Electric Company j

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November 1, 199] '93 CCT 28 P5 :48-PG&E Letter No. DCL-91-267 ,

.. 1 U.S. Nuclear Regulatory Comission I ATTN: Document Control Desk Washington, D.C. 20555 Re: Docket No. 50-323, OL-DPR-82 Diablo Canyon Unit 2 Licensee Event Report 2-91-007-00 Inadvertent Safety Injection While in Mode 5 Due to Personnel Error Gentlemen:

Pursuant to 10 CFR 50.73(a)(2)(iv), PG&E is submitting the enclosed i

Licensee Event Report (LER) concerning an inadvertent Safety Injection during a surveillance test caused by personnel error.

This event has in no way affected the health and safety'of the public.

Sir ere y, s wM Grehory M. yRueger cc: Ann P. Hodgdon Johr. B. Martin Philip J. Morrill Harry Rood Howard J. Wong CPUC <

Diablo Distributio..

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LICENSEE EVENT REPORT (LER) M '

1 racetsty manet p) occ Et t .amst e t ry man' is . 1 DIABLO CANYON UNIT 2 0l5 0l0l0]3l213 1 5 l tasa ta) INADVERTENT SAFETY 1.NJECTION WHILE IN MODE 5 DUE TO PERSONNEL ERROR l tvtart nave (s) u n sasets (si marant oAte tr> ointa racitivits :=vo6vto <si SEBq Daf TR VA K stG.llfifT At OEBe DAT TR IMEEIT Sa5SES (5) 0 5 0 0 0 l 10 06 91 91 -

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(5 ecHy in Mistract tielow and in text, NRC Form 366A)

LIctM5ft Cat 1ACT top THis Lie flF1 Y f L f DMON( asiper ( s MARTIN T. HUG, SENIOR REGULATORY COMPLIANCE ENGINEER ^*(*t 805 ,

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EXPECTED

$UBNIS$10N YES (if yes. corml et e EXPECTED SUBMIS$10N DATE) lXl NO D TE m) ansvas:1 os)

On October 6, 1991, at 0008 PDT, with Unit 2 in Mode 5 (Cold Shutdown) during the fourth refueling outage, two safety injection (SI) signals occurs G due to technicians operating Solid State Protection System (SSPS) control switches out of sequence with the surveillance test procedure (STP) they were performing. A four-hour, non-emergency report required by 10 CFR 50.72(b)(2)(ii) was made on October 6, 1991, at 0218 PDT.

The cause of the sis was personnel error. The technicians failed to utilize STP l-16D4, "Reconfiguring An SSPS Train in Modes 5 or 6," during the switch operating sequence.

STP I-1604 requires the SSPS Input Error Inhibit switch to be repositioned from " Normal" to " Inhibit" and the Mode Selector switch from " Test" to " Operate," in that order. The technicians repositioned the switches in reverse order on SSPS Trains A and B. Each train produced an SI signal.

All equipment performed as expected in Mode 5 during the SI. Unit 2 was returned to normal Mode 5 alignment on October 6, 1991, at 0015 PDT. Since emergency core cooling pumps were secured for maintenance, there was no water injection into the reactor coolant system.

The technicians discipline program. involved in this event were counseled in accordance with PGLE's positive A memorandum has been issued from the Vice President, Diablo Canyon Operations and Plant Manager, emphasizing the need for procedural compliance and verification.

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I LICENSEE EVENT REPORT (LER) TEXT CONTINUATION 179344 y ,- , , .- m -u, n m u...,., .m

{ DIABLO CANYON UNIT 2 0l5l0l0l0l3l2l3 91 -

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! 1. Plant Conditions Unit 2 was in Mode 5 (Cold Shutdown) at 0 percent power during the fourth i refueling outage. l t II. Description of Event t

A. Event:

i On October 5, 1991, two Instrument and Control (I&C) technicians were  :

l assigned to reconfigure Trains A and B of the Solid State Protection System (SSPS)(JE) from " Inputs In Normal /0utputs In Test" to " Inputs Inhibited /0utputs In Operate" per Surveillance Test Procedure (STP) 1-16D4, "Reconfiguring an SSPS Train ir. Modes'5 or 6." Since the SSPS was removed from service and both technicians had previously been .

tailboard u and had successfully performed the same STP earlier in the i week, no additional detailed tailboard was -conducted. The technicians l 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 F reman to reconfigure SSPS Trains A and B.

On October 6, 1991, at 0008 PDT, the following sequence of events took place within 30 seconds:

The "SSPS General Warning Train B" alarm cleared when the senior l technician repositioned the Train B Mode Select'or switch to the

" Operate" position prior to placing tha Input Error Inhibit switch in the " Inhibit" position. This sequence is opposite the required sequence of STP I-16D4. The senior technician did not have a copy of STP I-1604 in his possession when repositioning the switches The repositioning of this switch created a safety injection (SI) signal with SSPS Train B " Outputs in Operate" and " Inputs in Normal" and the Unit in a Mode 5 condition.

An "SSPS General Warning Train B" alarm occurred when the senior 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-1604.

The "SSPS General Warning Train A" alarm cleared when the junior technician, acting independently of the senior' technician, placed the SSPS Train A Mode Selector switch in the " Operate" position prior to placing the Input Error Inhibit switch in the " Inhibit" position. The junior technician did have a copy of the STP I-1604 summary sheet with 1 him at the time but failed to utilize the procedure while l

repositioning the switches. This placed SSPS Train A " Outputs in Operate" and " Inputs in Normal" and created a second SI signal with 1 the Unit in a Mode 5 condition.

55325/85K  :

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION 0004

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DIABLO CANYON UNIT 2 0l5l0l0l0l3l2l3 91 -

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An "SSPS General Warning Train A" alarm occurred when the junior technician placed the Train A Input Error Inhibit switch in the

" Inhibit" position. This placed SSPS Train A in the intended 1 configuration per STP l-16D4. I Following these events, the two technicians then verified that 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 the activities they had performed had caused sis. The technician who had reconfigured SSPS Train A retraced his steps and realized he had operated the switches in the incorrect order and informed his supervisor.

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

B. Inoperable Structures, Components, or Systems that Contributed to the Event:

None. ,

C. Dates and Approximate Times for Major Occurrences-

1. Oct. 6, 1991, at 0008 PDT: Event / discovery date. SSPS Train B and Train A SI signals occur, respectively.

2. Oct. 6, 1991, at 0015 PDT: All equipment and valves returned l to normal Mode 5 alignments.

4. Oct. 6, 1991, at 0218 PDT: A four-hour, non-emergency report I required by 10 CFR 50.72 (b)(2)(ii) was made.

D. Other Systems or Secondary Functions Affected: .

None.

E. Method of Discovery:

The event was immediately apparent to plant operators due to alarms l and indications received in the control room. -

F. Operators Actions:

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

55325/85K

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION 179944 t r e =Jee t s i past (3)

F OC I LIT T NAME ()) 00Csti MLMeta (3) s)

T TO' DIABLO CANYON UNIT 2 0l5l0l010l3l2l3 91 -

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0l0 4l"l5 ini n13 G. Safety System Responses:

The following Engineered Safety Features (ESF) actuations occurred:

• Safety injection (BQ)

• Vital 4kV busses transferred to startup power (EK)

• Phase "A" containment isolation (JM)

• Feedwater isolation (JB)

• Auxiliary saltwater pump 2-1 (BI)(P) started

• Main steam line isolation (JI)

• Diesel generators 1-3 and 2-2 started (EK)

• Residual heat removal pump 2-1 (RP)(P) started 111. Cause of the Event A. Immediate Cause:

The immediate cause of the event was improper configuration of the-SSPS while in Mode 5 operation (i.e., inputs in " Normal", outputs in

" Operate").

B. Root Cause:

The root cause of the ave.nt is personnel error. The senior technician did not use the procedure and the junior technician did not follow the sequence of steps in STP I-16D4.

C. Contributory Cause:

1. The technicians did not' practice self-verification in accordance with 1&C Department policy memorandum, " Policy For Unit / Channel / Component Self Verification," dated June 30, 1988.

2. The technici3ns did not practice concurrent verification in accordance with NPAP C-104, " Independent Verification Of Operating Activities."

j IV. Analysis of the Event Unit 2 was in Mode 5 when this event occurred with the reactor coolant system (RCS)(AB) temperature less than 200*F and the RCS not pressurized.

55325/85K l

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION 179944 '.,

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DIABLO CANYON UNIT 2 Ol5l0l0l0l3l2l3 91 -

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0l0 5 l 'l 5 fini (17)

All ESF equipment functioned as intended, as listed in paragraph II.G.

above.

No water was injected into the RCS since emergency core cooling system pumps were secured for refueling cutage maintenance.

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

V. Corrective Actions A. Immediate Corrective Actions; After determining the cause of the event was personnel error, Operations returned the plant to normal Mode 5 alignments. l B. Corrective Actions to Prevent Recurrence:

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

2. A memorandum has been issued by the Vice President, Diablo Canyon Operations and Plant Manager, emphasizing the need for procedural compliance, self-verification, concurrent verification, and independent verification.

3. The technicians responsible for this event were counseled in accordance with the PG&E Positive Discipline Program.

VI. Additional Information A. Failed Components:

None.

B. Previous Similar Events:

None.

55325/85K