05000254/LER-1993-009

LER 93-009-00:on 930714,SBGT Methyl Iodide Test Failed Due to Age of Charcoal Combined W/Stringent Test Criteria. Replaced Charcoal Absorber in Both Trains of Sbgt. W/930806 Ltr

ML20056D825
Person / Time
Site:	Quad Cities
Issue date:	08/13/1993
From:	Bax R, Luebbe R COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-009-04, LER-93-9-4, RLB-93-105, NUDOCS 9308180097
Download: ML20056D825 (5)

LER-2093-009,

Event date:
Report date:
2542093009R00 - NRC Website

text

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C;mmonw lth Ediz:n O-- Quad Cites Nuclear Power Station 22710 206 Avenue North Cordova. Ilunois 61242-974D Teiephone 309%54 2241

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s' RLB-93-105 August 6, 1993 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Reference:

Quad Cities Nuclear Power Station Docket Number 50-254, DPR-29, Unit One Enclosed is Licensee Event Report (LER)93-009, Revision 00 for Quad Cities Nuclear Power Station.

This report is submitted in accordance with the requirements of the Code of Federal Regulations, Title 10, Part 50.73 (a)(2)(v)(C). The licensee shall report any event or condition that alone could have prevented fulfillment of (V the safety function of structures or systems that are needed to control the release of radioactive material.

Respectfully, COMMONWEALTH EDISON COMPANY QUAD CITIES NUCLEAR PO ER STATION 4 R. L. Bax

/ Station Manager RLB/TLB/pim Enclosure cc: R. Stols T. Taylor INP0 Records Center NRC Region III O :so m STMGR\lO593.kLB C

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LICENSEE EVENT REPORT (LER) Fonn Res.2.0 p* Sty Name (1) ,

Ducka Number Gl Page Q) l I -

_lcties t'ait one 0 15 P P P P P H lor l l Title (O SBGT Methyllodide Test Failure Due To Age Of Charteal Event Date (5; LER Number tol Report Date (J) Other lachties la,<dved (El Mouth Day near near Saguentaal Re,auen Mouth Day near l achty DucLa humberts)

Number Number Names Q=dCn= 4

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0 P P P P P P P l 0 [7 i P W p V p -

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O p 0 p i p 9 p 0 p p p p l l l OPERATING THIS REPORT IS SUhMTTTED PUR5U ANT 101HE REQUIRutENT5 OF MCFR MODE (9) (Check one or more of the following) (11)

I 20.402(b) 20.405(c) 50.73(a)(2)Ov) 73.71(b) i luw LR 20.405(a)(1)6) 50.36(c)(1) I50.73(a)G)(v) -73.71(c)

LEVEL 20.405(a)(1)6i) 50.36(c)G) 50.73(a)(2)(vii) Other (Specify

00) l p 20.405(a)(1)6ii) 50.73(a)C)6) 50.73(a)C)(viii)(A) in Abstract 20.40$(a)(1)6v) 50.73(a)C)6i) 50.73(a)C)(viii)(B) below and in 20.405(a)(1)(v) 50.73(a)C)6ii) 50.73(a)(2)(x) Text)

LICENSEE CONTACT FOR 1H15 LLk (12)

NAME TELEPHONE S UMBEA AREA CODE Rachel Luebbc. Tech staff Engineer. Ext. 2119 3 p p 6 p p l.p p p p COMPLETE ONE LINE FOR EACH COMPONLNT F AILURL DEACR1hED IN T111S REPOkT (13)

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K NO Date (15) l l l All5'l RACI (Lamit to 14u0 spaces, i.e., apprvsunately fif teca smgie-space ty peunttens hues) (1 }

ABSTRACT:

On Wednesday, July 14, 1993, Unit one was in cold shutdown and Unit two was in the run mode at 20% of rated core thermal power. On June 29, 1993 the A SBGT train charcoal methyl iodide efficiency was shown to be 75.4% Tech Spec 3.7.B.2.a.3 require a methyl iodide efficiency of 90%. Both SBGT trains charcoal were replaced by July 4th. At 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> on July 14th, the results of the old B Standby Gas Treatment (SBGT)[VI] train charcoal showed a methyl iodide efficiency of 72.1%. Therefore, before the charcoal replacement on both trains of SBGT on July 4th, both trains of SBGT were inoperable. A 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Emergency Notification Phone call was made at 1610 hours0.0186 days <br />0.447 hours <br />0.00266 weeks <br />6.12605e-4 months <br /> on July 14, 1993.

The apparent cause of the failed methyl iodide efficiency test is the age of charcoal combined with the more stringent test criteria.  ;

One corrective action was to replace the charcoal adsorber [ ADS) in both trains of SBGT upon discovery of the A Train methyl iodide efficiency failure. Followup corrective actions are to ,

install modification M04-0-92-013, which replaces the pneumatic flow switches with electronic  ;

% switches. This modification will allow relaxation of the testing criteria. Until the i fication is completed and the Tech Spec revision approved, the station will test the methyl (

iodide efficiency of the charcoal every 6 months. }

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LER254193\004.WPF '

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Fons Rev.2.0 FACILITY NAME (1) DOCKET NL3tBER Q) LLR NL}iliER t4 PAGE 0)

Year Sequestaal kernwa

, Number Number Cities Unit One o p l0 p p p p }4 9 p -

O p p a p 2 lOF p l TLXT 1mergy industry Identifscation Systeun LLII5) tooes are identiGad in the text as [XX)

PLANT AND SYSTEM IDENTIFICATION:

Gereral Electric - Boiling Water Reactor - 2511 MWt rated core thermal power.

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EVENT IDENTIFICATION: SBGT Methyl Iodide Test Failure Due to Age of Charcoal.

i A. CONDITIONS PRIOR TO EVENT Unit: One Event Date: July 14, 1993 Time: 1507 hours0.0174 days <br />0.419 hours <br />0.00249 weeks <br />5.734135e-4 months <br /> Reactor Mode: 1 Mode: Shutdown Power Level: 0%

This report was initiated by Licensee Event Report 254/93-009.

SHUTDOWN (1) - In this pasition, a reactor scram is initiated, power to the control rod l drives is removed, and the reactor protection trip systems have been deenergized for 10 seconds prior to permissive for manual reset.

B. DESCRIPTION OF EVENT 0n Wednesday, July 14, 1993, Unit One was in cold shutdown, and Unit Two was in the run l 0' mode at 20% of rated core thermal power. On Tuesday, June 29, 1993 at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> Nuclear Consulting Services (NUCON) informed the station that_the charcoal sample previously sent from the "A" Standby Gas Treatment (SBGT)[VI) had a methyl iodide removal efficiency of 75.4%. A 90% methyl iodide removal efficiency is required per Technical Specification 3.7.B.2.a.3.

The "A" SBGT train was declared inoperatie and the "B" SBGT train was started to prove ,

operability. On Wednesday, June 30, 1993 the failed charcoal was removed from the A Train of SBGT. On Thursday, July 1,1993 new charcoal trays were installed with a methyl iodide efficiency of 98.94%. After successful completion of the 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> operability run the A Train of SBGT was declared operable at 1820 hrs on Friday, July 2, 1993.

On Friday, July 2nd the "B" SBGT was taken out of service for replacement of the charcoal adsorber [ ADS). At that time, a test canister was taken out of the old charcoal for methyl  ;

iodide lab analysis. The replacement charcoal has an efficiency of 99.7%. After successful completion of the 10 hour1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> operability run the B Train of SBGT was declared operable on Sunday, July 4th at 1815 hours0.021 days <br />0.504 hours <br />0.003 weeks <br />6.906075e-4 months <br />.

Results of the "B" SBGT old charcoal methyl iodide efficiency were received by the station at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> on Wednesday, July 14th. The results showed an efficiency of 72.1%. A4 hour Emergency Notification Phone call was made on July 14, 1993 at 1610 hours0.0186 days <br />0.447 hours <br />0.00266 weeks <br />6.12605e-4 months <br />.

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Form Rev.2.0 l OKILil Y NAME O s DOEKET NUMBER (2; .LER NUMllER (6) PAGE0; l

Year Sequmtaal Rensnun Number Number l

_ Chks Unt ow 0 p p p p p p p 9 p -

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O p 2 pF p l l 1 EXT lacrgy ladustry ldatifacatu,n System (Lil5p codes are idatified an the test as (XX) i C. APPARENT CAUSE The failure of the charcoal to successfully pass the methyl iodide test is attributed to the age of charcoal and new stringent test criteria. The charcoal for the A train of SBGT was installed in 1990, and was originally ordered in 1988. The charcoal for the B Train was installed in 1987. The last tests for methyl iodide efficiency were done per ASTM D3803-1979 at 30* C and 70% relative humidity. The 70% relative humidity (R.H.) was previously used because SBGT contains a heater which controls the relative humidity.

Since that test, it was discovered that a loss of instrument air would prevent the heater from functioning and reducing the relative humidity in the train. Therefore, the station ;

committed to doing the methyl iodide test for SBGT at 30' C and 95% relative humidity per  ;

ASTM D3803-1989 (see LER 254/92-028), because the use of the heater to control humidity 4

could no longer be assumed.

The ASTM D3803-1989 standard states, " Decreasing the relative humidity of the test i generally increases the efficiency of the methyl iodide removal by activated carbon. The  :

, water vapor competes with the methyl iodide for adsorption sites on the carbon, ..."  !

I Therefore, switching from a 70% relative humidity test to a 95% relative humidity test will '

cause the methyl iodide efficiency of the charcoal to decrease.

l A review of maintenance activities since November 1991, showed no actions that would have

, degraded the charcoal. Painting activities have been controlled by procedure since July 1991; therefore, a painting event in the area of SBGT did not cause the charcoal to degrade. ,

D. SAFETY ANALYSIS l l

This event is being reported in accordance with 10CFR 50.73(a)(2)(v)(C). The licensee .

shall notify the NRC for any event or condition that alone could have prevented the l fulfillment of the safety function of structures or systems that are needed to control the '

j release of radioactive material. i l i

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, _ LICENSEE EVENT REPORT (LER) TT_XT CONTINUATION Form Rev. 2.0 ACILITY NAME (1) DOCKET NDihER Gl LER NDiBER 46) PAGE 0)

Year l maumtmal kersuon iumber Number d Citiem Unit One O p p p p p p p 9 p -

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O p 2 pF p l pEXT bwrgy industry idesat4 cation 6stesu (Lils codes are idstinesi in the test as IXX]

Based on calculations the safety consequences of this event would have been a reduction in the design basis dose margin from 260% to 257% had a loss of Coolant Accident (LOCA) occurred. The release of radioactive material wou~. not have exceeded Control Room (GDC

19) and Off-site Dose (10CFR100) limits had a loss of Coolant Accident (LOCA) occurred.

Methyl iodide makes up about 4% of the iodine source seen during a post-accident situation.

The other 96% are elemental and particulate iodides. Trapping of elemental and particulatt iodides involves physical adsorption only, and the efficiency of activated carbon will

typically be at least 99%. Trapping of methyl iodides involves a chemical adsorption

. process, which is why the carbon is impregnated with Potassium Iodine (KI). Methyl iodide removal efficiency is intended to gauge the degree of degradation of the impregnation of the carbon and not the actual removal efficiency of the system. Assuming that the removal efficiency of the elemental and particulate iodides are also affected by the degradation of the carbon, the design basis dose would increase by 165%. However, since the removal efficiency of 96% of the iodides was unaffected then the design basis dose would increase by 2.7%

E. RECOMMENDED CORRECTIVE ACTIONS When the test results were received from the A train of SBGT, both train's charcoal adsorbers were replaced with new charcoal tested to the 30' C, 95% R.H.1989 standard.

This work was completed on both trains on July 3, 1993. The new A train charcoal has an O efficiency of 98.9% and the new B train charcoal has an efficiency of 99.7%. These efficiencies are well above the 90% required by Technical Specifications.

Modification M04-0-92-013 to replace the pneumatic flow switches on SBGT will be completed.

Once this modification is completed and the submitted Technical Specification revision is approved, then the station can return to the 30' C and 70% relative humidity methyl iodide test (NTS# 2542009211302). Until that time, the station will test the methyl iodide efficiency of the charcoal every 6 months at 30* C and 95% R.H.1989 standard (NTS# 2541809300901).

F. REVIEW OF PREVIOUS EVENTS l There have been no previous events of the SBGT charcoal failing the methyl iodide efficiency test.

G. COMPONENT FAILURE DATA .

Currently, the Nuclear Plant Reliability Data System (NPRDS) does not cover the SBGT charcoal adsorber. The NPRDS system will be revised to include this component. This and all future failures of the charcoal adsorber will be reported through NPRDS.

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