ML17251B045

LER 88-002-00:on 880308,level of Boric Acid Storage Tank Less than 2,000 Gallons in Violation of Tech Specs.Caused by Partial Plugging of Level Sensing Lines.Sensing Lines Cleaned Prior to Declaring Tank operable.W/880406 Ltr

ML17251B045
Person / Time
Site:	Ginna
Issue date:	04/06/1988
From:	Backus W, Snow B ROCHESTER GAS & ELECTRIC CORP.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
LER-88-002, LER-88-2, NUDOCS 8804140044
Download: ML17251B045 (10)

Text

ACCE1ZMTED DISTRIBUTION DEMONSTR ON SYSTEM REGULA RY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR: 8804140044 DOC. DATE: 88/04/06 NOTARIZED: NO DOC I(ET FACIL: 50-244 Robert Emmet Qinna Nuclear Plant. Unit ii Rochester G 05000244 AUTH. NAME AUTHOR AFFILIATION BACKUSI W. H. Rochester Qas 5 Electric Corp.

SNOWI B. A. Rochester Gas 8c Electric Corp.

RECIP. NAME RECIPIENT AFFILIATION

SUBJECT:

LER 88-002-00: on 880308 level instrument malfunction caused R.

boric acid vol to be less than 2i 000 gallons.

W/8 ltr.

DISTRIBUTION CODE: IESED COPIES RECEIVED: LTR i ENCL i SIZE:

TITLE: 50. 73 Licensee Event Report (LER)I Incident Rpt> etc.

S NOTES: License Exp date in accordance eith iOCFR2I 2. 109(9/19/72). 0500024 REC IP IENT COPIES REC IP IENT COPIES A ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD1-3 LA 1 1 PD1-3 PD 1 1 STAHLEI C 1 1 INTERNAL: ACRS MICHELSON 1 ACRS MOELLER AEOD/DOA 1 1 AEOD/DSP/NAS 1 1 AEOD/DSP/ROAB AEOD/DSP/TPAB 1 1

,ARM/DCTS/DAB 1 1 DEDRO 1 1 NRR/DEST/ADS 7E 0 NRR/DEST/CEB 8H 1 1 NRR/DEST/ESB 8D 1 1 NRR/DEST/ICSB 7 1 1 NRR/DEST/MEB 9H 1 1 NRR/DEST/MTB 9H 1 1 NRR/DEBT/PSB 8D 1 1 NRR/DEST/RSB 8E 1 NRR/DEST/SGB 8D 1 NRR/DLPG/HFB 10 1 NRR/DLPG/GAB 10 1 NRR/DOEA/EAB 11 1 1 NRR/DREP/RAB 10 1 1 NRR/DREP/RPB 10 NRR/DR I S/SI B 9A 1 1 NRR/PMAS/ILRB12 1 1 tg G~CL~E 02 1 1 RES TELFORDI J 1 1 R

RES/DE/EIB 1 1 RES/DRPS DIR 1 1 RGN1 FILE 01 1 1 EXTERNAL: EGhQ GROH M 4 FORD BLDG HOY. A H ST LOBBY WARD 1 1 LPDR NRC PDR 1 1 NSIC HARRIS' NSIC NAYS> Q 1 1 h

TOTAL NUMBER OF COPIES REQUIRED: LTTR 45 ENCL 44

U.t. IIUCI tAII lllOUCAYOIIYCOUUIttIOH ASSIIOVlO LICENSEE EVENT REPORT ILER) TEXT CONTINUATION OMl IIO. 3150MIOI tXSIlltt 4/llltt IIAUt III OOCIItY NW&tllIll Lt1 IIUUttllIll SACI CITY ytAA e llQUAMTIAl r, V CION M U A R.E. Ginna Nuclear Power Plant 0 6 0 0 0 2 4 4 88 002 000 2ot'0 8 mcruAUU~O~ ~~ttlca maxim PRE-EVENT PLANT CONDITIONS Unit heat-up from the Annual Refueling and Maintenance Outage was on hold to per form testing and equipment lineups required by the Plant Technical Specifications prior to exceeding a Reactor Coolant System (RCS) temper-ature of 350 F.

The "A" Boric Acid Storage Tank (BAST) was isolated and held so that a post-modifi.cation heat tracing test on its discharge line could be performed. The "B" BAST was lined up for operation with an indicated level of approxi-mately 684.

The previous shi.ft had added two batches of Boric Acid Solution, (i.e. approximately 800 gallons) to the "AI'AST and had transferred some Boric Acid solution from the "B" BAST to the "A" BAST to bring the "A" BAST level to approximately 124. Nhile this transfer was in progress the Control Room operators assured themselves by BAST level indication that they were maintaining greater than the minimum 2000 gallons in the "B" BAST (i.e. > 664 level) required by the plant Technical Specifications with the RCS above 200 F ~ The 12% level was required in the "A" BAST to allow energizing the tank immersion heaters. This would facilitate the heat tracing test by heating the tank to normal operating temperature.

During the previous shift it was observed that one of the two "B" BAST level indicators was reading offscale high indicating a possible sensing line partial plugging problem. A request was made to the Instrument and Control (I&C) department to clean out the BAST level sensing lines per procedure PT-21 (Cleaning Boric Acid Tank Sensing Lines). This procedure is performed once per week as required by the plant Technical Specifications when the BASTs are required to be operable and any other time the BAST level indicators indicate sensing line partial plugging. The cleaning of the BAST level sensing lines consists of reaming out the nitrogen bubbler tubes for each level indicating system. These bubbler tubes become partially plugged with precipitated Boric Acid where the nitrogen gas bubbles into the tank.

MAC SOAU tttA IICtI

gl U.t. NUCLtAII Ill4ULAYONYCOMMItSON NNC lena 5WA 1045 I LICENSEE EVENT REPORT (LER) TEXT CONTINUATION AtlAOVtOOMt NO, 5150&11M tX ~ INt5- tlllltt OOCKtY NlNNlll151 Ltll NUMtlllItl ~ A45 151 SAC I LIYY NAMt Ill ytAN a~~ ttQUtNYIAL N M A P: AtVNIQN N M N

~~ ~

R.E. Gonna Nuclear Power Plant 0 s 0 0 0 2 4 4 8 8 P P 2 0 03 OFO 8 YtxT (P gwe N ~ MC IGNI ~tl 117)

The I&C Department had responded to the request to clean out the BAST level indicator sensing lines and was perform-ing PT-21.

DESCRIPTION OF EVENT A. EVENT:

On March 8, 1988 at 0135 EST the RCS temperature and pressure was at 340 F and 350 psig respectively and the I&C Department had gust completed PT-21.

Following the completion of PT-21 the Control Room operators observed that the "B" BAST level was indicating 454. This level indication was below the Technical Specification requirement of > 664 level for one operable BAST and constituted a plant condition prohibited by Technical Specifications.

B. INOPERABLE STRUCTURES, COMPONENTS'R SYSTEMS THAT CONTRIBUTED TO THE EVENT:

The "A" BAST at this time was indicating 404 level but the tank test was and was deemed still isolated for the heat tracing inoperable. Had the "A" BAST not been isolated, the two together would have contained greater than the required amount of Boric Acid per Technical Specifications.

C. DATES AND APPROXIMATE TIMES FOR MAJOR OCCURRENCES:

0 March 7, 1988, 2230 EST: Estimated time arid date "B" BAST was decreased below required level 0 March 8, 1988, 0135 EST: I&C Department completes PT-21 0 March 8, 1988, 0135 EST: Discovery date and time 0 March.8, 1988, 0205 EST: "B" BAST level restored to within Technical Specification limits NAC YOWM 555A 15451

U.t. NUCLCAN A4OULATONT COVM1441ON NIIC Pena 544A 14441 LICENSEE EVENT REPORT ILER) TEXT CONTINUATION AftlIOV40OM5 NO5150&10A 5XNA45'/51I45 I'ACILITYNANt ill OOCXtT NWM4N Ql L4N NUV551 141 PAO4 (41 44QM4NTIAL v 4VNION TTAll M NMM A R.E. Gonna TINT IN AWe ~ N N ltNA44 ~ ~ ower INC fess Plant

~W 11Tl 0 S 0 0 0 0 0 2 004 OF 0 8 D. OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED:

None E. METHOD OF DISCOVERY:

The event was immediately apparent due to indications in the Control Room.

F. OPERATOR ACTION:

The Control Room operators, upon discovery of the event took. immediate action to restore the "B45 BAST level to meet the Technical Specification require-ments. This was done by transferring Boric Acid solution from the "A" BAST to the "B" BAST and was completed in approximately 30 minutes.

G. SAFETY SYSTEMS RESPONSES:

None III. CAUSE OF EVENT A. IMMEDIATE CAUSE:

The "B" BAST was less than the required 2000 gallons of Boric Acid solution because of level indication inaccuracies due to partial plugging of its level indicator sensing lines.

NAC 4OAV 444A 15451

~ .

UA. NUCLSAA ASOULATOAY COMMISSION LICENSEE EVENT REPORT ILERI TEXT CONTINUATION AttAOVSO OMS NO. SISOWIOl SX ~ IASS SnIISS OOCKST NLNASA ISI LSA NUMSSA ISI FACILITY NAMS III VSAA SSOUSNTIAL V4ION M 1 4 V TSXT IS MNe MMS 4 MSvS44 ~ ~

R.E. Gonna Nuclear Power Plant ANC AM4 maSI IITI 0 S 0 0 0 244 8 8 0 0 2 0 0 05<<08 B. ROOT CAUSE:

The results of a root cause investigation determined that there were two major root causes with a possible third that contributed to the event. These are as follows:

The type of level instrumentation systems employed by the BASTs are susceptible to inaccur-acies due to sensing line partial plugging from Boric Acid precipitation.

2 ~ The "B" BAST was declared operable prior to performing PT-21 on the level sensing lines even though the above susceptibility to inaccuracies due to sensing line partial plugging was known.

U 3 ~ The original Westinghouse recommendation for the BAST nitrogen bubbler system was that the nitrogen gas for this system should be at a pressure of 125 psig and a temperature of approximately 100 F. The pressure recommendation is met but the temperature recommendation was lower by approximately 50 F. It could be theorized that the lower the nitrogen gas temperature bubbling into the tank through the sensing lines, the greater the likelihood of precipitating the concentrated boric acid solution thus partially plugging the sensing lines.

AL S S OF EVENT This event is reportable in accordance with 10 CFR 50.73, Licensee Event Report System, item (a)(2)(i)(B) which recpxires reporting of "any operation or condition prohibited by the Plants Technical Specifications in that the plant was in a condition prohibited by Technical Specifications".

Technical Specif ication (TS) 3. 2. 2 (c) states, in part, that the reactor shall not be taken above cold shutdown (i.e. RCS temperature > 200 F) unless the boric acid tanks together contain a minimum of 2,000 gallons of a 12% to 13% by weight boric acid solution at a temperature of at least 145oF.

NAC SOAV SSSA (04SI

U.I. IIUCLCAII1l4ULATOAY COMSIISSIOII IIIIC Pena SSSA (04SI UCENSEE EVENT REPORT ILER) TEXT CONTINUATION AffAOVEO OUI IIO. SI SOW(04 fXf(ASS: Sfl(ISS fAC(LITT IIAISS (11 OOCI(tT ~lS (Sl LSS IIUMClll(SI SSOVSHTIAL )yC N M 1 R.E. Gonna Nuclear Power Plant o s o o o 24 488 0 2 000 6oF 08 TEXT ld ~~ O lr0eAW ~ +4WIHVASSC fora ~W (1Tl TS 3. 2. 3 (c) states, in part, that the above requirement

. can be modified to allow one boric acid tank out of service provided a minimum of 2,000 gallons of a 124 to 134 by weight boric acid solution at a temperature of at least 145 F is contained in the operable tank. The plant did not meet this requirement because of having less than 2,000 gallons in the operable tank. The operable tank contained approximately 1600 gallons of boric acid solution at its low point.

The estimated time the "B" BAST was out of specifications due to not meeting the > 2,000 gallons of boric acid solution requirement was approximately 3.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />. - Zt is assumed the "B" BAST contained > 2,000 gallons of boric acid solution until the operators transferred part of the "B" BAST to the "A" BAST on March 7, 1988 at 2230 EST, to cover the heaters. This assumption is based on the mass input and output from the "B" BAST since filled starting March 2, 1988. The "B" BAST again contained it was initially 2,000 gallons of boric acid solution at approximately 0205 EST, March 8, 1988 after PT-21 had been performed and the, operators "B"

had transferred part of the. "A" BAST back to the BAST.

An assessment was performed considering both the safety consequences and implications of this event with the following results and conclusions:

There were no operational or safety consequences or implications attributed to the ",B" BAST containing less than the TS required volume of boric acid solution because:

0 The plant was stable at 340 F RCS temperature with no reactivity changes taking place.

0 The reactor make-up and boration systems were fully operational.

MAC fOALI SSSA (045 l

U.t. IIUCLtAIIlllOULATOAYCOMMIttIOM ArrlIOVtOOMt HO, tISOMI04 LICENSEE EVENT REPORT ILER) TEXT CONTINUATION tXrIAtt tlalnt OOCIItT HW%tll Ill LtA IIUMCtllItl f I LITT MAlat II I AC saauaMriAL V4KIH YaAII 4 M II H M 000 "0 cur i~~ afaaai ~

R.E. Gonna Nuclear Power Plant

~~AaaC a maZ IITI 0 s 0 0 0 2 g 4 002 7 8 o If additional boration was needed beyond the boric acid contained in the "B" BAST, the refueling water storage tank was available to the charging pump suction containing > 300,000 gallons of > 2000 ppm solution.

o The plant TS basis states that, "the quantity of boric acid in storage from either the boric acid tanks or the refueling water storage tank is sufficient to borate the reactor coolant in order to reach cold shutdown at any time during core life. Approximately 1800 gallons of 124 to 134 solution of boric acid are required to meet cold shutdown conditions. Thus a minimum of 2000 gallons in the boric acid tanks is specified". The intent of this basis had already been met as the reactor coolant system was already borated to greater than the cold shutdown condition during the event.

Based on the ab'ove it can be concluded that the public's health and safety was assured at all times.

V. CORRECT ACTION A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:

0 The operators immediately upon discovery of the event transferred part of the "A" BAST boric acid solution to the "B" BAST to return the "B" BAST to greater than the required volume of 2000 gallons. This was done in approximately orie half hour.

B. ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:

1. Rochester Gas and Electric Corporation (RG&E) will review alternate level indicating systems for the BASTs and make recommendations as necessary.

4IIC fOAM aaaA Itttl

U4. IIUCLCAIIALOULAYOIIYCOMMICNOM MAC Awry 0NA l041l LICENSEE EVENT REPORT (LER) TEXT CONTINUATION ~OVCO OMC MO, 1150MIOI CxrlA0$: 00ll00 SACILITY NAME ill OOCKCY INNill I1l LlllIIUMCCII ICI ~ AO0 I1I yCAA (Yr', SIQVINT<AI. ~ ~ VQIOlv U II ~ Q M R.E. Gonna Nuclear Power Plant 0 6 0 0 0 244 88 002 00 08 oFO 8 7NIT(gaWe~4l00MIW ~~JWCAsN~WII1l 2 Operating procedure 0-1.-1D (Pre-Heatup Plant Requirement Check List) will be changed to

~

require PT-21 to be performed gust prior to declaring the Boric Acid Tanks operable.

3 ~ RG&E will review the possibility that the low nitrogen gas temperature could be the root cause of the sensing line partial plugging and make recommendations as necessary.

ADDITIONAL INFORMATION A. FAILED COMPONENTS:

None.

B. PREVIOUS LERs ON SIMILAR EVENTS:

A similar LER event historical search was conducted with the following results: No documentation of similar LER events at Ginna Station could be identified.

C. SPECIAL COMMENTS:

None.

MAC tOAM 000A l041l

ROCHESTER GAS AND ELECTRIC CORPORATION ~ 89 EAST AVENUE, ROCHESTER, N.Y. 14649-0001 Abaca cour "io 546 2 C.

April 6, 1988 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Subject:

LER 88-002, Level Instrument Malfunction Causes Boric Acid Volume To Be Less Than 2000 Gallons, A Condition Prohibited By Technical Specifications R.E. Ginna Nuclear Power Plant Docket No. 50-244 In accordance with 10 CFR 50.73, Licensee Event Report System, item (a) (2) (i) (B). which requires a report of, "any operation or condition prohibited by the Plant's Technical Specifications", the attached Licensee Event Report LER 88-002 is hereby submitted.

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

Very truly yours,

)

ruce A. h ow Superintendent of Nuclear Production xco U. S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna USNRC Resident Inspector pt'oS %737~3