ML17265A427

LER 98-003-00:on 980904,actuations of CR Emergency Air Treatment Sys Occurred.Caused by Radon build-up During Temp Inversion.Air Samples Were Taken & Determined That Source of Radiation Was Naturally Occurring Radon.With 981005 Ltr

ML17265A427
Person / Time
Site:	Ginna
Issue date:	10/05/1998
From:	Mecredy R, St Martin J ROCHESTER GAS & ELECTRIC CORP.
To:	Vissing G NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-98-003, LER-98-3, NUDOCS 9810150007
Download: ML17265A427 (12)

Text

CATEGORY REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9810150007 DOC.DATE: 98/10/05 NOTARIZED: NO DOCKET FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G 05000244 AUTH.iIAME . AUTHOR AFFILIATION ST MARTIN,J.T. Rochester Gas & Electric Corp.

MECREDY,R.C. Rochester Gas &,Electric Corp.

RECIP.NAME RECIPIENT AFFILIATION VISSING,G.S.

SUBJECT:

LER 98-003-00:on 980904,actuations of CR emergency air treatment sys occurred. Caused by radon build-up during temp inversion.Air samples were taken & determined that source of DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR j radiation was naturally occurring radon. With 981005 ltr.

NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72).

ENCL I TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

SIZE: 7 05000244 G

RECIPIENT COPIES RECIPIENT COPIES ID, CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD1-1 PD 1 1 VISSING,G. 1 1 INTERNAL: AEOD PD RAB 2 2 AEOD/S PD/RRAB 1 1 C 1 1 NRR/DE/ECGB 1 1 NRR/DE E 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOHB 1 1 NRR/DRCH/HQMB 1 1 NRR/DRPM/PECB 1 1 NRR/DSSA/SPLB 1 1 RES/DET/EIB 1 1 D RGN1 FILE 01 1 1 0

EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE,J H 1 1 NOAC POORE,W. 1 1 NOAC QUEENER,DS 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 ~ 1 N

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD) ON EXTENSION 415-2083 FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 22* ENCL 22

/g ANO ROCHESTER GAS AND ELECTRIC CORPORATION 69 EAS T AVENUE, ROCHES TER, N.Y. 14649-0001 AREA CODE 716-546-2700 ROBERT C. MECREDY Vice President Nucleor Operations October 5, 1998 U.S. Nuclear Regulatory Commission Document Control Desk Attn: Guy S. Vissing Project Directorate I-1 Washington, D.C. 20555

Subject:

LER 1998-003, Radon Build-up During Temperature Inversion Results in Actuations of Control Room Emergency Air Treatment System R.E. Ginna Nuclear Power Plant Docket No. 50-244

Dear Mr. Vissing:

In accordance with 10 CFR 50.73, Licensee Event Report System, item (a) (2) (iv), which requires a report of, "any event or condition that resulted in manual or automatic actuation Protection of any Engineered Safety Feature (ESF), including the Reactor System (RPS)", the attached Licensee Event Report LER 1998-003 is hereby submitted.

These events have in no way affected the public's health and safety.

Very truly yours, xc: Mr. Guy S. Vissing (Mail Stop 14B2)

Project Directorate I-1 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 U.S. NRC Ginna Senior Resident Inspector 9810i 50007 'sts1005 PDR ADOCK 05000244 S PDR

NRC FORM 366 (6-1996)

U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)

.(See reverse for required number of requesl: 50 hrs.

licensing process snd fed ~

APPROVED BY OMB NO. 3150-0104 EXPIRES 06/30/2001 Estimated burden per response to comply with this mandatory lessons learned are incorporated into th informat'caocdon k to industry. Forward oomments regsrdi burden esbmate to the Records Management Branch (T4) F33), UB. Nuctes Regutatoy Comnssskar. Washington. DC 205580001, and to the Psperwo Reduction Project (31500104), Oflice of Management and Budget Washington, DC 20503. If an information collection does not dispby digits/characters for each block) currently valid OMB control number, the NRC may not conduct or sponsor and a person is not required to respond to, the Informathn collection.

FACILITYNAME l1) DOCKET NUMBER l2) PAGE (3)

R.E. Ginna Nuclear Power Plant 05000244 1 OF 6 TITLE ISI Radon Buildup During Temperature Inversion Results in Actuations of Control Room Emergency Air Treatment System FACIUlYNAME DOCKET NUMBER MONTH SEOUENTIAL REVISION OAY NUMBER NUMBER MONTH OAY 05000 FACIUTY NAME OOCKET NUMBER 09 04 1998 1998 003 00 10 05 1998 05000 OPERATING MODE (9) 20. 2201 (b) 20.2203 (a) (2) lv) 50.73(e) l2)(i) 50.73le)(2)(viii)

POWER LEVEL (10) 20.2203(a) l2)(i) 20. 2203(a) (3) (ii) 50.73ta) (2)(iii) 73.71 OTHER 20.2203(e) (2)(iii) 50.36(c) I )

1 50.73(a)(2) lv) Specify in Abstract below 20.2203te)(2)(iv) 50.36(c)(2) 50.73(e) (2)(vii) or in NRC Form 366A NAME TELEPHONE NUMBER Sne!use Ares Cede!

John T. St. Martin - Technical Assistant (716) 771-3641 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13) r?

'j:c K%

REPORTABLE REPORTABLE CAUSE SYSTEM COMPONENT MANUFACTUROI TO EPIX :I L".E CAUSE SYSTEM COMPONENT MANUFACTURER TO EPIX

%4@

SUPPLEMENTAL REPORT EXPECTED I14) MONTH OAY YEAR EXPECTED YEB SUBMISSION X (If yes, complete EXPECTED SUBMISSION DATE). NO DATE I15) 12 10 98 ABSTRACT (Limit to 1400 spacos, i.e., approximately 15 single. spaced typewritten lines) (16)

On September 4, 1998, at approximately 0740 EDST, the plant was in Mode 1 at approximately 100% steady "state reactor power. Control Room Radiation Monitors reached thei.r alarm setpoints, and actuated the Control Room Emergency Air Treatment System to isolate the Control Room atmosphere to and from outside air. On September 15, 1998, at approximately 0051 EDST, the same event occurred. On September 18, 1998, at approximately 0452 EDST, the same event occurred.

On these three dates, an atmospheric temperature inversion was present, and an unusually high concentration of Radon built up and was trapped due to the inversion. Control Room Radiation Monitors alarmed due to the presence of this unusually high concentration of naturally occurring radioactive Radon and Radon decay products.

Immediate action was taken to determine the source of radiation. In these events, air samples were taken which determined that the source of radiation was naturally occurring Radon and Radon decay products. These air samples confirmed that fission product activity was not the cause.

No immediate corrective actions were required. A Root Cause Analysis is being conducted to confirm that no other factors contributed to these events. When the Root Cause Analysis is completed, a supplement to this LER will be submitted.

NAC FOAM 366 (6.1996)

0 0

"~

l

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION I6-1999)

LlCENSEE EVENT REPORT (LER)

TEXT CONTINUATION SEQUENTIAL REVISION NUMBER NUMBER R. E. Ginna Nuc)ear Power Plant 05000244 1998 - oos - 00 2 OF 6 TEXT (Ifmora space is required, use additional copies of NRC &rm 366A) )17)

I. PRE-EVENT PLANT CONDITIONS:

On September 4, 1998, at approximately 0740 EDST, the plant was in Mode 1 at approximately 100% steady state reactor power. Unrelated to plant activities, an atmospheric temperature inversion was present. A temperature inversion limits the dispersion of matter from the ground into the upper atmosphere.

II. DESCRIPTION OF EVENT:

A DATES AND APPROXIMATE TIMES OF MAJOR OCCURRENCES:

o , September 4, 1998, 0740 EDST: First event date and time.

0 September 4, 1998, 0740 EDST: Discovery date and time.

o September 15, 1998, 0051 EDST: Second event date and time.

o September 15, 1998, 0051 EDST: Discovery date and time.

September 18, 1998, 0452 EDST: Third event date and time.

September 18, 1998, 0452 EDST: Discovery date and time.

o September 18, 1998, 1631 EDST: Invalid actuation of Control Room Emergency Air Treatment System.

B. EVENT:

The Control Room Radiation Monitors monitor outside air in the vicinity of the Control Room. A high radiation signal on one of these monitors will initiate the Control Room Emergency Air Treatment System (CREATS) filtration train and isolate each air supply path to and from the Control Room.

On September 4, 1998, the plant was in Mode 1 at approximately 100% steady state reactor power. Due to the temperature inversion, there was an unusually high concentration of naturally occurring radioactive Radon and Radon decay products in the lower atmosphere. At approximately 0740 EDST, Control Room Radiation Monitors reached their alarm setpoints. The GREATS actuated and isolated the Control Room atmosphere to and from outside air upon reaching these setpoints. Samples were taken to determine the isotopic content of the air in the Control Room. These samples determined that there was an unusually high concentration of Radon and Radon decay products from the outside air, and indicated that fission product activity was not the cause of the increase in radioactivity.

NRC FORM 366A I6-1998)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION 16-1996)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION SEQUENTIAL REVISION NUMBER NUMBER R. E. Ginna Nuclear Power Plant 05000244 1996 ~ - 003 - 00 3 OF 6 TEXT iifmore space is required, use addi(ional copies of NRC Form 366'AJ I171 On September 15, 1998, at approximately 0051 EDST, Control Room Radiation Monitors reached their alarm setpoints and the CREATS isolated the Control Room atmosphere to and from outside air. Again, a temperature inversion was present, and samples determined that there was an unusually high concentration of Radon and Radon decay products from the outside air.

On September 18, 1998r at approximately 0452 EDST, Control Room Radiation Monitors reached their alarm setpoints and the GREATS isolated the Control Room atmosphere to and from outside air. For a third time, a temperature inversion was present, and samples determined that there was an unusually high concentration of Radon and Radon decay products from the outside air.

C. INOPERABLE STRUCTURESr COMPONENTSr OR SYSTEMS THAT CONTRIBUTED TO THE EVENT:

None D. OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED:

None E. METHOD OF DISCOVERY:

These three events were immediately apparent due to the actuation of CREATS to isolate the Control Room atmosphere to and from outside air.

F. OPERATOR ACTION:

During these three events, the Control Room operators acknowledged Hain Control Board annunciators associated with the radiation monitor alarms and actuation of the CREATS, entered Alarm Response Procedure AR-E-11 (Control Room HVAC Isolation), and notified higher supervision and the NRC. They confirmed that Control Room Radiation Honitor R-37 (which measures particulate radiation) was locked in to the alarm condition. Independent air samples were requested, and when the results of these air samples confirmed the presence of radioactivity (Radon and Radon decay products), the Control Room operators determined that valid actuations of the CREATS had occurred.

The Shift Supervisor subsequently notified the NRC per 10 CFR 50.72 (b) (2)

(ii), non-emergency four hour notification, at approximately 1115 EDST on September 4, 1998.

On September 15, 1998, the NRC was notified at approximately 0442 EDST. On September 18, 1998, the NRC was notified at approximately 0915 EDST. This last notification was slightly beyond the four hour timeframe due to delays in confirming the presence of Radon and Radon decay products.

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION l6-19981 LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION SEQUENTIAL REVISION NUMBER NUMBER 05000244 1998 oos 4 OF 6 R. E. Ginna Nuclear Power Plant OO TEXT /ifmore spece is required, use edditionel copies of lVRC Form 366Al (17)

G. SAFETY SYSTEM RESPONSES:

The CREATS'actuated to isolate the Control Room atmosphere to and from outside air when the radiation monitors reached their alarm setpoints.

III. CAUSE OF EVENTs A. IMMEDIATE CAUSE:

The immediate cause of the actuation of the GREATS was Control Room Radiation Monitors reaching their alarm setpoints, resulting in isolation of the Control Room atmosphere to and from outside air.

B. INTERMEDIATE CAUSE:

The intermediate cause of the radiation monitors reaching their alarm setpoints was increased radioactivity of the outside air, due to an unusually high concentration of Radon and Radon decay products.

C. ROOT CAUSE:

The underlying cause of the unusually high concentration of Radon and Radon decay products was an atmospheric temperature inversion, which trapped the naturally occurring Radon in the lower atmosphere, limiting the dispersion of matter from the ground into the upper atmosphere. Samples taken confirmed that the radioactivity was due to the temperature inversion, and not due to fission product activity.

These three events occurred as stated above. On September 18, 1998, at approximately 1631 EDST, a fourth CREATS actuation occurred. Control Room operators checked the R-37 monitor, and discovered that there was no alarm condition. There was no temperature inversion present, and there had been no significant increase in radioactivity as monitored by R-37. It was determined that this fourth event (September 18 at 1631 EDST) was an invalid actuation.

Based on this invalid actuation coming so soon after three apparently valid CREATS actuations, a Root Cause Analysis (RCA) has been initiated to confirm that no other factors contributed to the three apparently valid CREATS actuations that occurred earlier in September.

NRc FQRM 366A (6-1998)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION 16.19981 LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION SEQUENTIAL REVISION NUMBER NUM8ER R. E. Ginna Nuclear Power Plant 05000244 1998 oos - 00 5 OF 6 TEXT /Ifmore speoe is required, use additionel copies of /VRC Form 366A1 l17l IV. ANALYSIS OF EVENT:

These three events are reportable in accordance with 10 CFR 50.73r Licensee Event Report System, item (a) (2) (iv), which requires a report of, "any event or condition that resulted in manual or automatic actuation of any Engineered Safety Feature (ESF) including the Reactor Protection System (RPS)". CREATS is listed in NUREG-1022 as an example system of what the NRC staff considers to be a system "provided to mitigate the consequences of a significant. event."

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 GREATS actuation because:

o The CREATS provides a protected environment from which operators can control the plant following an uncontrolled release of radioactivity.

There was no uncontrolled release of radioactivity which occurred on either September 4, September 15, or September 18.

0 The GREATS actuation was in response to increased radioactivity in the vicinity of the Control Room. However, the increased radioactivity was due to naturally occurring Radon and Radon decay products. The increase in radiation detected was not due to any plant activity. Specifically, it was not due to an increase in fission product activity nor an uncontrolled release of radioactivity.

o GREATS functioned as per design, to isolate the Control Room in response to levels of radioactivity that resulted in reaching the alarm setpoints on the Control Room Radiation Monitors.

Based on the above, it can be concluded that the plant operated as designed, that and that the public's health and safety there were no unreviewed safety questions, was assured at all times.

V. CORRECTIVE ACTION:

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

At the conclusion of the three temperature inversions, and after the Control Room Radiation Monitors decreased below their alarm setpoints, the CREATS actuation signal was reset; and normal ventilation was restored to the Control Room.

NRC FORM 3BBA IB-1998)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION I6.1999)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION ~

SEQUENTIAL REVISION NUMBER NUMBER R. E. Ginna Nuclear Power Plant 05000244 1998 - oo> - 00 6 OF 6 TEXT (ifmore speceis required, use edditionel copies of iVRC Form 366A/ I17)

B ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:

A Root Cause Analysis has been initiated to determine if other factors contributed to the three apparently valid GREATS actuations.

o A supplement to the'ER will be submitted by December 10, 1998.

VI. 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 with the same root cause at Ginna Station could be identified.

C. SPECIAL COMMENTS:

Until 1998, Ginna Station did not consider the CREATS to be an ESF. In 1998, new NRC guidance was promulgated in NUREG-1022, Revision 1. NRC specifically listed the Heating, Ventilating and Air Conditioning System for Control Room as an example of an ESF system. Therefore, Ginna Station reporting procedures were revised in 1998 to be in accordance with this NRC guidance.

Individuals recall that, prior to 1998, there were some CREATS actuations at Ginna Station. However, these actuations were not reportable at those times.

Since these earlier actuations were not reportable, no documents exist to confirm any of these earlier occurrences.

NRC FORM 366A I6-1998)"

0