ML20045H892

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LER 93-005-01:on 930311,discovered That Automatic RPS Actuation Occurred on 930222 & Not Immediately Reported to Nrc.Caused by Personnel Error.Memo Sent to All Licensed Operators/Personnel Re Reporting requirements.W/930709 Ltr
ML20045H892
Person / Time
Site: Millstone Dominion icon.png
Issue date: 07/09/1993
From: Borchert R, Scace S
NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-005, LER-93-5, MP-93-545, NUDOCS 9307220083
Download: ML20045H892 (4)
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N^RTHEAST UTILITIES oen~=' omca San S"a' S"ha o "aa" l Nsfe$"MaIsIeNsettIE eComra P.O. BOX 270 Il=E**5IE'U*I5*'"

U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

Reference:

Facility Operating License No. DPR-65  :

Docket No. 50-336 Licensee Event Report 93-005-01 Gentlemen:

This letter forwards update Licensee Event Report 93-005-01.

Very truly yours.

NORTHEAST NUCLEAR ENERGY COMPANY )

nw Stephen E. cace r  ;

Vice President - Millstone Station l l

SES/RB:ljs

Attachment:

LER 93-005-01 cc: T. T. Martin, Region I Administrator P. D. Swetland, Senior Resident inspector, Millstone Unit Nos.1, 2 and 3 G. S. Vissing, NRC Project Manager, Millstone Unit No. 2 l

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l 200 9307220083m 930709 r l

PDR ADOCK 05000336 F f hE [h) '/W u

i NAC Form 3p6 U S. NUOLE AR REGULATOAY COMM!SSION APPROVED OMB NO. 3150-0104 (6-@9) EXPIRES 4/30/92 I Estimated duroen per response to cornoiy with trus inforfration conection request: 50 0 hrs. F orw ard

. Comments regarding Durcen estimate to the Recoros i LICENSEE EVENT REPORT (LER) ano Reports Management Branen ip-530,. u S Nuciw

., Regulatory Commission. Washington DC 20555, and to the Paperwork Reevcton Project (3150-0104). Omce of Manageme-1 and Buopet. Washington DC 20503 F ACUTY N AME lij DOCKET NUMBER (2) PA9 '

Atillstone Nuclear Power Station Unit 2 of sl ol of of 3 l3 ls 1lorj013 TITLE 14)

Automatic Reactor Protection System Actuation While Shutdown EVENT DATE 154 LER NUMBER r6) REPOAT DATE (71 CT NEA F ACiUTlE 5 NVOLVED 181 MONTE DAY YEAR YEAR J NYm MONTH DAY YEAq F ACOTY NAMES f of si ol ol of I I I

0 2 2l2 9 3 9 l3 0l0l5 0l 1 Ol7 0 l9 9l3 ofslololof l l l 1

i OPERATING THtS REPORT IS BEING SUBM!TTED PURSUANT TO THE REQUIREMENTS or 10 CFR i: ICheck one or more of the foliowingir11) 20.402(b) _

20. 402(c) J Sc.73 tall 2)(sv) _

73.71 (b)

POWER 20 405 Ea)(1)(.) 50 36tc)(1) _

50 73ta):2)(v) _

73.71(c)

,EVP t 0l0l0 20 405 tan 1un) 50.3 sten 2) _

So. 73. (a H2nvu) _ LTg,Rg gg , i Text, NRC Form 366A) 20 405taltt)(mi 50. 73(a H2)(0 60.73 t a H24 (m0 ( A) ]

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20 40Sf all1Hav) 50. 73(e H2) D0 50.73ia H2)(vw)(B) l i 20 40S t al r11 fivi 50.73 f a)(2)(iid 50 73taH2)lx) l UCENSEE CONTACT FOR THis LE A (121 NAME TELEPHONE NUMBER ARE A CODE Robert Borchert, Unit 2 Reactor Engineer, Ext. 4418 2 0l3 4l4l7l-l1l7l9l1 COMDLETE ONE UNE FOR E ACH COMPONENT FAIL URE DESCRIBED N TH:S REPORT N37 OAUSE SYSTEC COMPONENT $N~ Y , l CAUSE SYSTEU COMPONENT pppo i lII I I I I II I I I I I II I I i l I III I i 1 SUDDL EMENTAL REPORT EXPECTED (14) MONTH DAY YEAR SUBMrSSION VES & ves. como ete EXPECTED SUBMSSION D ATE) NO DATE W g j j ABSTA ACT f umit to 1400 spaces. e e. , apprownately fdteen smg1e-space typewritten tenes) (16)

On Alarch 11,1993, at 1625 hours0.0188 days <br />0.451 hours <br />0.00269 weeks <br />6.183125e-4 months <br />, with the plant in Niode 1 at 100cc power, it was discovered that an automatic Reactor Protection System (RPS) actuation had occurred on February 22, 1993 which had not been immediately reported to the USNRC. The USNRC was notified of this event on A1 arch 11,1993 at 1707 hours0.0198 days <br />0.474 hours <br />0.00282 weeks <br />6.495135e-4 months <br />.

On February 22,1993, at 0811 hours0.00939 days <br />0.225 hours <br />0.00134 weeks <br />3.085855e-4 months <br />, with the plant in Afode 3 at Occ power, Reactor Coolant System (RCS) pressure at 2267 psia, RCS average temperature at 527 degrees Fahrenheit, and all control rods fully mserted, an automatic RPS actuauon occurred during an unplanned cooldown event. The cooldown caused the steam I generator pressures to decrease to approximately 707 psia, which caused an automatic RPS actuation on low steam generator pressure.

The only automatic safety system response during the above event was the opening of the reactor trip circuit I breakers. Due to personnel error, this event was not immediately reported to the USNRC pursuant to the l requirements of Paragraph 50.72(b)(2)(ii), reporting any event or condition that results in manual or automatic j actuation of any Engmeered Safety Feature System, including the Reactor Protection System. 4 NRC Form 366 (6-89)

.-- . . . .~ .~ - - - - . - - ~ - - - . -. ~-

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l NRC Form 366A U S. NUCLEAR REoVLAToRY COMMISSION APPROVED OMS No. 3150-01r4 (6-891

  • EXPIRE S: 4/30/92 Estimated buroen per response to comply witn tNs LICENSEE EVENT REPORT (LER) g*g,coQon4*go5h,50 f,,*,5, m ,7f,8',d,,,

c TEXT CONTINUATION and r4eports Management Branen u>530L U S. Nuclear Regulatory Commiss#on. Washington. DC 20555 and to the Pacerwork Aeduction Prceert (3150-01041. ottsce c1 Management and Buoget WasNngton. DC 20503 F AcOTY NAME (1) DOCKET NUVBER (2) t FA NUMBEn m PAGE(31 YEAR N N eudeus -

eenmoi Atillstone Nuclear Power Station U*I 2 OF

0l 5l 0l 0l 0l3 l3 l6 9l3 0l 0l 5 0l1 0l 2 0l3 l l

TEXT Of more space is reauired. use a3ditional NRc Form 366A s1 (17)

1. Descrirition of Event i On Alarch 11,1993, at 1625 hours0.0188 days <br />0.451 hours <br />0.00269 weeks <br />6.183125e-4 months <br />, with the plant in Alode 1 at 100G power, during an investigation of i a plant cooldown event, a review of the computer alarm typer printouts revealed that an automatic l Reactor Protection System (RPS) actuation had occurred on February 22,1993 which had not been- j immediately reported to the USNRC. The USNRC was notified of this event on Alarch 11,1993 at i

1707 hours0.0198 days <br />0.474 hours <br />0.00282 weeks <br />6.495135e-4 months <br />.  ;

On February 22,1993, at OS11 hours, with the plant in Alode 3 at 0% power, Reactor Coolant System (RCS) pressure at 2267 psia, RCS average temperature at 527 degrees Fahrenheit, and all control rods  ;

fully insened, an automatic RPS actuation occurred during an unplanned cooldown event. The cooldown j was initiated during stroking of the main turbine intercept stop valves in_ accordance with procedure l- EOP 2526. " Reactor Trip Recovery." The turbine trip signal caused the feedwater regulating bypass i valves to automatically open to 759. The feedwater regulating bypass valves automatically closed when steam generator water level reached S5G. The cold feedwater injection into the steam generators cooled l the bulk water. This caused the steam generator pressures.to decrease to approximately 707 psia. An j automatic RPS actuation occurred on low steam generator pressure. The only automatic safety system ,

response was the opening of the reactor Trip Circuit Breakers (TCBs). The operator actions taken -)

included closing the Alain Steam Isolation Valves (A1SIVs) in response to the cooldown. )

Due to personnel error, this event was not immediately reported to the USNRC pursuant to the requirements of Paragraph 50.72(b)(2)(ii), reponing any event or condition that results in manual or i automauc actuation of any Eng neered Safety Feature System, including the Reactor Protection System.  !

Prior to the above event, the RPS was reset to allow the main turbine to be reset for surveillance tesung. j

, The operators involved in this event considered the RPS to be out-of-service because the reactor was 1 l shutdown with all control rods fully inserted. Based on this fact, the personnel involved did not consider l the RPS actuauon to be a reactor trip event and therefore did not perform the required event notifications.

II. Cauce of Event l

The root cause of the cooldown event was poor attention to detail by the operators during the stroking of the main turbme intercept stop valves. The operators should have taken actions to stop the injection of cold feedwater to the steam generators following the turbine trip signal in accordance with a caution statement in procedure EOP 2526, " Reactor Tnp Recovery."

The cause of the failure to immediately report the automatic RPS actuation to the USNRC was due to personnel error and a lack of sensithity to automatic RPS actuation reporting requirements when the j reactor is in a shutdown condition. Pnor to the above event, the RPS was reset to allow the main turbine to be reset for surveillance testing. The operators involved in this event considered the RPS to be out-of-service because the reactor was shutdown with all control rods fully inserted. Based on this fact, the personnel involved did not consider the RPS actuation to be a reactor trip event and therefore did not perform the required event notifications.

i Ill. Analysts of Event l This event is being reported pursuant to the requirements of Paragraph 50.73(a)(2)(iv), reporting any event or condition that resulted in manual or automatic actuation of any Engineered Safety Feature System, including the Reactor Protection System.

There were no safety consequences from this automatic RPS actuation since the reactor was already shutdown with all control rods fully inserted, and maintained in a shutdown condition throughout the actuation.

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orm 366

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NRC Form 366A U.S. NUCLE AR REGULATORY CoMMiSSloN APPROVED OMS No. 3150-0104 ,

16-09) ExPlRES 4/30/92 i

. Estimated burden per response to comply witn this  !

'n'"m8taa m'*** "o"'5' 50 0 " 5- " * * 'd LICENSEE EVENT REPORT (LER) Comments regardcngb' u .1en estimate 'to the"Recorcs i i

TEXT CONTINUATION and Reports Management Branen <p-s3oh V S. Nuclear I Regulatory commssion, Washmg$on. DC 20555, are to ,

the Paperwork Reducten Project (3150-0104L ottice of 1 Management and Budget Washington DC 20503. l FACILITY NAME (1) DOCKET NUMBER (2) i F A NUMac A m PAGE (3)

YEAR N N

- m era Millstone Nuclear Power Station Unit 2 0l Sj 0l 0l 0l3 l3 l6 9l3 OF 0l 0l 5 0l1 0l 3 0l3 l TEXT tit more space is required. use additional NRC Form 366A's) (17)

! IV. Corrective Action I

A memorandum has been sent to all licensed plant reactor operators and key management personnel concerning the reporting requirements for any event or condition that results in a manual or automatic actuation of any Engineered Safety Feature System, including the Reactor Protection System, regardless of plant operating / shutdown conditions.

Procedure EOP 2526, " Reactor Trip Recovery," has been revised to more clearly identify the operator actions to be taken when stroking the main turbine intercept stop valves.

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I A memorandum has been sent to all licensed plant reactor operators and key management personnel l concerning the operability requirements of the RPS for all modes of plant operation.

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V. Addnional Information )

Similar LER'S: 91-008 Ells Code Identifiers for Referenced Components:

Reactor Protection System: JC-5-C490 ,

Intercept Stop Valves: TG-ISV-GOS4 Feedwater Regulating Bypass Valves: SJ-FCV-C635 i 1

Main Steam Isolation Valves: SB-ISV-A585 l Trip Circuit Breakers: JC-52-GOSO I

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