05000244/LER-1998-003, :on 980904,actuations of CR Emergency Air Treatment Sys Was Noted Due to Invalid Causes.Caused by Various Degraded Components in CR RM Sys.Creats Actuation Signal Was Reset & Normal Ventilation Was Restored
| ML17265A708 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 07/22/1999 |
| From: | St Martin J ROCHESTER GAS & ELECTRIC CORP. |
| To: | |
| Shared Package | |
| ML17265A707 | List:
|
| References | |
| LER-98-003, NUDOCS 9907280131 | |
| Download: ML17265A708 (12) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(viii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 2441998003R00 - NRC Website | |
text
NRC FORM 366 IB.IBBBI U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
(See reverse for required number of digits/characters for each block) fXARMrNQr resp nBe to'~mph'NL'04NP01 hfonnation coBection request: 50 hrs.
Reported lessons learned are incorporated into the licensing process and fed back to hdustry. Forward comments regarding burden estimato to the Records Management Branch (T-6 F33). U.S. Nuclear Regulatory Commission, Washington, DC 205554001
~ and to the PapenNork Reduction Project (3150%104), Office of Management and Budget, Washington, DC 20503. 'Ifan information collection does not display a currently valid OMB control number. the NRC may not conduct or sponsor, and a FACILITYNAMEI'l R. E..Ginna Nuclear Power Plant DOCKET NUMBER I2]
05000244 PAGE (3) 1 OF 9
TITLEte)
Actuations of Control Room Emergency Air Treatment System Due to Invalid Causes EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED(6)
MONTH OAY 09 04 SEOUENTIAL NUMBER REISlON NUMBER 1998 1998 003
02 MONTH 07 OAY YEAR 22 1999 FACILITYNAME FACILITYNAME OOCKETNUMBER
, 05000 DOCKET NUMBER 05000 OPERATING MODE (9)
POWER LEVEL (10) 100 20.2203(a)(2) (i) 20.2203(a) (2)(ii) 20.2203(a)(3) (ii) 20.2203(a)(4) 50.73(a)(2) (iii) 50.73(a)(2)(iv)
THIS REPORT IS SUBMITTED P URSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check 50.73(a) (2) (i)(B) 20.2203(a)(2)(v) 20.2201(b) 50.73(a) (2)(ii) 20.2203(a) (3) (i) 20.2203(a)(1) one or more)
(11) 50.73(a) (2) (viii) 50.73(a)(2)(x) 73.71 OTHER 20.2203(a)(2)(iii) 20.2203(a) (2) (iv) 50.36(c) (1) 50.36(c)(2)
LICENSEE CONTACT FOR THIS LER (12) 50.73(a) (2) (v) 50.73(a)(2)(vii)
Specify in Abstract below or in NRC Form 366A NAME TELEPHONE NUMBER (Inaiude Ares Cade)
John T. St. Martin - Technical Assistant (716) 771-3641
CAUSE
SYSTEM COMPONENT MANUFACTURER REPORTABLE TO EPIX
CAUSE
SYSTEM COMPONENT MANUFACTURER REPORTABLE TO EPIX SUPPLEMENTAL REPORT EXPECTED (14)
YES (If yes, complete EXPECTED SUBMISSIONDATE).
I':?;:
>'.;.:,I'O X
EXPECTED SUBMISSIDN DATE (15)
MONTH OAY YEAR ABSTRACT (Limitto 1400 spaces, 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.
One of the Control Room Radiation Monitors reached its alarm setpoint, and actuated the Control Room Emergency Air Treatment System to isolate the Control Room atmosphere to and from outside air. The same event occurred on September 15, 1998 at approximately 0051 EDST, September 18, 1998 at 0452 EDST, September 18, 1998 at 1631 EDST, October 20, 1998 at 0403 EDST, October 27, 1998 at 0706 EST, February 13, 1999 at 1430 EST, and March 8, 1999 at 1310 EST.
These events were originally believed to be valid actuations (except for the events of September 18 at 1631 EDST, October 20, February 13 and March 8, which were immediately determined to be invalid actuations).
Immediate action was taken to determine the source of radiation and/or cause of the actuations.
No immediate corrective actions were required.
A revised Root Cause Analysis was conducted and is outlined in Section III.C. This root cause analysis has determined that there were various degraded components in the Control Room Radiation Monitoring system.
These degraded components resulted in electronic spikes in the readings on the monitors.
The higher concentrations of Radon and Radon decay products caused the margin to the trip setpoint to be reduced.
Thus, in the presence of elevated Radon levels, the electronic spikes caused a setpoint to be exceeded.
When elevated Radon levels were not present, larger spikes also caused a setpoint to be exceeded.
The degraded components, resulting in electronic spikes, were the root cause of the Control Room Emergency Air Treatment System (GREATS) actuations.
All GREATS actuations, including those originally believed to be valid actuations, were, in fact, invalid actuations.
Corrective action to prevent recurrence is outlined in Section V.B.
9907280$.3i 990722 PDR ADOCK 05000244 a
m TTto(B IBOB)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITYNAME I1)
R.E. Ginna Nuclear Power Plant DOCKET I2) 05000244 LER NUMBER I6) yEAR SEOUENTIAE REVISION NUMBER NUMBER 1999 -
003
02 PAGE I3) 2 OF 9
TEXT (ifmore spaceis required, use additional copies ofNRC Form 366Ai I17)
PRE-EVENT PLANT CONDITIONS:
(The pre-event conditions are discussed only for the first event of September 4, 1998.
See Section II of this report for additional information.)
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
September 4, 1998, 0740 EDST: First event date and time.
September 15, 1998, 0051 EDST: Second event date and time.
September 18, 1998, 0452 EDST: Third event date and time.
September 18, 1998; 1631 EDST.: Fourth e'vent date and time.
October 20, 1998, 0403 EDST: Fifth event date and time.
October 27, 1998, 0706 EST: Sixth event date and time.
February 13, 1999, 1430 EST: Seventh event date and time.
March 8, 1999, 1310 EST: Eighth event date and time.
B.
EVENT:
'I The Control Room Radiation Monitoring system monitors outside air in the vicinity of the Control Room.
The Control Room Radiation Monitor consists of three (3) separate channels that analyze a common sample of outside air being supplied to the Control Room.
Channel R-.36 monitors for noble gas.
Channel R-37 monitors for particulate.
Channel R-38 monitors for iodine. A high radiation signaI on one of these monitors will initiate the Control Room Emergency AirTreatment System (GREATS) 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 Radon and Radon decay products in the lower atmosphere.
At approximately 0740 EDST, Control Room Radiation Monitor R-37 reached its alarm setpoint.
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 present.(6 1999) e LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITYNAME I1)
R.E. Ginna Nuclear Power Plant DOCKET I2) 05000244 LER NUMBER I6)
YEAR SEBUENTIAL RENSION NUMBER NUMBER 1998
003
02 PAGE I3) 3 OF 9
TEXT fffmore spaceis required, use additional copies of NRC Form 366A/ I17)
On September 15, 1998, at approximately 0051 EDST, Control Room Radiation Monitor R-37 reached its alarm setpoint 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, 1998, at approximately 0452 EDST, Control Room Radiation Monitor R-37 reached its alarm setpoint and the CREATS 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.
On September 18, 1998, at approximately 1631 EDST, Control Room Radiation Monitors R-36 and R-37 spiked above their alarm setpoints and the GREATS isolated the'Control Room atmosphere to and from outside air. Air samples gave no indication that Radon and Radon decay products were present, and this actuation was immediately determined to be an invalid actuation.
Troubleshooting began.
A recorder was installed to monitor equipment performance and a root cause team was organized to determine the cause(s) of the CREATS actuations.
On October 20, 1998, at approximately 0403 EDST, another CREATS actuation occurred.
Control Room operators determined that Control Room Radiation Monitor R-36 had spiked above its alarm setpoint.
There was no temperature inversion present, and there had been no significant increase in radioactivity as monitored by the Control Room Radiation Monitors. This actuation was immediately determined to be an invalid actuation.
On October 27, 1998, at approximately 0706 EST, Control Room Radiation Monitor R-37 reached its alarm setpoint.
Prior to this time, the GREATS had been manually isolated for troubleshooting of the Control Room Radiation Monitors. Therefore, when the radiation alarms occurred, no GREATS actuation or Control Room alarm occurred.
Later that morning (at approximately 1050 EST),
Instrument and Control (ISC) technicians observed the radiation monitor alarm on a local panel outside the Control Room, and notified Control Room operators of the alarm.
Another temperature inversion was determined to be present.
With the exception of the September 18 (at 1631 EDST) and October 20 events, it was believed, at the time of these actuations, that the CREATS actuations were valid and these events were reported to the NRC per the requirements of 10 CFR 50.72.
A root cause investigation team was assembled.
It included a radiation monitor specialist, who was contracted to assist in interpreting the data and to provide additional guidance in data collection methods, and a vendor technician, who was brought in to assist in the equipment troubleshooting process.
The vendor technician provided vendor test procedures and acceptance criteria. A thorough review was conducted of all relevant data that was recorded on the plant process computer system (PPCS) for these events.
Substantial corrective maintenance was performed on the Control Room Radiation Monitors.(9.1999)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITYNAME (1)
R.E. Ginna Nuclear Power Plant DOCKET (2) 05000244 LER NUMBER (6)
SEQUENTIAL NUMBER NUMBER 1996
003
02 PAGE (3) 4 OF 9
TEXT llfmore space is required, use additional copies of NRC Form 366A/ (17)
The team determined that, in the presence of elevated Radon levels, electronic spikes caused a
setpoint to be exceeded.
When elevated Radon levels were not present, larger spikes also caused a
setpoint to be exceeded.
All GREATS actuations, including those originally believed to be valid actuations, were, in fact, invalid actuations.
See Section III.C of this report for details.
During the time the root cause team was active, there were more invalid GREATS actuations.
On February 13, 1999 at approximately 1430 EST, and on March 8, 1999 at approximately 1310 EST, Control Room Radiation Monitor R-36 reached its alarm setpoint.
Since the GREATS had been manually isolated for troubleshooting of the Control Room Radiation Monitors, no isolation occurred.
Under the guidance of the vendor technician, various components were tested and compared to vendor specifications.
The high voltage power supplies had excessive ripple. The existing power supplies were sent back to the vendor for refurbishment.
The Control Room Radiation Monitor calibration procedures were enhanced to collect and trend data.
After all the above issues were addressed and spikes were still occurring, all of the connections on the printed circuit boards in the ratemeters were inspected.
These inspections identified degraded soldered connections.
Various circuit boards were repaired or replaced.
After the above modifications and repairs were completed, the PPCS plots were compared to the original plots.
There was a noticeable decrease in the magnitude of random fluctuation in the signals.
INOPERABLE STRUCTURES, COMPONENTS, OR SYSTEMS THAT CONTRIBUTED TO THE EVENT:
None D.
OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED
None E.
METHOD OF DISCOVERY
The events of September 4, 15, 18 and October 20 were immediately apparent due to the actuation of GREATS to isolate the Control Room atmosphere to and from outside air.
For the events of October 27, February 13 and March 8, troubleshooting was being performed and GREATS had been manually isolated for troubleshooting of the Control Room Radiation Monitors.(6 1999)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITYNAME I1)
'I R.E. Ginna Nuclear Power Plant DocKET I2) 05000244 LER NUMBER I6) m SEQUENTIAL REVISIQN NUMBER NUMBER 1998
003
02 PAGE I3) 5 OF 9
TEXT (lfmore space is required, use additional copies of NRC Form 366AJ I17)
F.
OPERATOR ACTION
During the events of September 4, 15, 18 (at 0051 EDST), and October 20, the Control Room operators acknowledged Main Control Board annunciators associated with the radiation monitor alarms and actuation of the GREATS, entered Alarm Response Procedure AR-E-11 (Control Room HVAC Isolation), and notified higher supervision and the NRC.
In each case, they confirmed that one of the Control Room Radiation Monitors was locked in 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 GREATS 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; On October 27, 1998, the NRC was notified at approximately 1439 EST.
The events of September 18 at 1631 EDST, October 20, February 13, and March 8, were immediately determined to be invalid actuations.
NRC notifications per 10 CFR 50.72 were not required for these events.
For the events of October 27, February 13 and March 8 (that occurred when the GREATS was actuated and the Control Room was already isolat'ed) no operator response or action was warranted.
G.
SAFETY SYSTEM RESPONSES:
For the events of September 4, 15, 18, and October 20, the GREATS actuated to isolate the Control Room atmosphere to and from outside air.
For the events of October 27, February 13 and March 8, the CREATS was already actuated as a prerequisite for troubleshooting the system, so no response occurred.
III.
CAUSE OF EVENT
A.
IMMEDIATECAUSE:
In each case, the immediate cause of the actuation of the CREATS was one of the Control Room Radiation Monitors reaching its alarm setpoint, resulting in isolation of the Control Room atmosphere to and from outside air.(6 1998)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITYNAME I1)
R.E. Ginna Nuclear Power Plant DOCKET I2) 05000244 LER NUMBER I6) y@R BEBUEIITIJL Ra IUM IIUMBER IIUMBER 1998 -
003
02 PAGE I3) 6 OF 9
TEXT llfmore space is required, use additional copies of NRC Form 366Al ('I7)
B.
INTERMEDIATECAUSE:
The intermediate cause of the CREATS actuations was the elevated concentration of Radon and Radon decay products during some of the actuations.
The elevated levels of radon masked the true root cause.
C.
ROOT CAUSE:
It has been determined that there were various degraded components in the Control Room Radiation Monitoring system.
These degraded components resulted in electronic spikes in the readings on the monitors.
The higher concentrations of Radon and Radon decay products caused the margin to the trip setpoint to be reduced.
Thus, in the presence of elevated Radon levels, the electronic spikes caused a setpoint to be exceeded.
When elevated Radon levels were not present, larger spikes also caused a setpoint to be exceeded.
The degraded components, resulting in electronic spikes, were the root cause of the Control Room Emergency AirTreatment System (CREATS) actuations.
All GREATS actuations, including those originally believed to be valid actuations, were, in fact, invalid actuations.
For the actuations originally believed to be valid, a contributing 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 increased radioactivity was due to the temperature inversion, and not due to fission product activity.
The issues evaluated by the root cause team included intermittent problems in combination with the instances of atmospheric temperature inversions that were causing unusually high concentrations of Radon and Radon decay products at the time of some of the actuations.
Samples taken confirmed that the radiation monitor alarms were not due to fission product activity. The root cause team followed many leads and hypotheses.
A list of significant conclusions follows:
The radiation monitoring equipment had a history of actuations during electrical switching events which normally occurred on the system.
For example, when the R-37 particulate monitor paper switch position was changed, the R-36 noble gas monitor spiked.
When pumps and relays in the vicinity of the skid were switched, both the particulate and noble gas monitors spiked.
As a corrective action, noise suppression was added.
This eliminated the spikes from switches, pumps and relays.
Long term and short term PPCS plots were reviewed. The long term plots of times when the equipment was known to have actuated GREATS often did not indicate the increase above the setpoint.
However when the signals were expanded in very short time increments it was verified that the setpoints were exceeded.
The very short time frame and shape of the signals indicated that the signals were actually noise spikes and not valid increases in radiation levels.IB.IBBB)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITYNAME I1)
R.E. Ginna Nuclear Power Plant DOCKET I2) 05000244 LER NUMBER I6)
SEQUENTIAL REVISION NUMBER NUMBER 1998 -
003 02 PAGE I3) 7 OF 9
TEXT /Ifmore spaceis required, use addirional copies of NRC Form 366AJ I17)
Recorders were installed to monitor each radiation monitoring channel.
They revealed erratic signals.
The signals would spike high and drop to zero counts in seconds.
The vendor technician indicated these fluctuations were normal due to the age and design of the equipment.
IRC technicians inspected all internal wires for degraded insulation or loose connections.
The insulation on all three detector cables for the monitors were found to be degraded.
In addition, some ribbon cables were found degraded.
All degraded cables and connectors were replaced.
The System Engineer reviewed the setpoint calculations.
The setpoints on the particulate and iodine channels were set conservatively low. Setpoints were increased to ensure that normal increases in the level of Radon and Radon Decay products would not result in undesired actuations, while still meeting all safety and design requirements.
IV.
ANALYSIS OF EVENT
All CREATS actuations, including those originally believed to be valid actuations, were, in fact, invalid actuations.
Several of these events were originally believed to be valid, and therefore reportable 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 of any Engineered Safety Feature (ESF) including the Reactor Protection System (RPS)".
GREATS 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 CREATS 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 from any of these events.
The calibration data showed that the Control Room Radiation Monitors responded normally when exposed to a known radiation source.
GREATS functioned as per design to isolate the Control Room atmosphere to and from outside air when their alarm setpoints were reached on the Control Room Radiation Monitors.IB 1996) e LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITYNAME I1)
R.E. Ginna Nuclear Power'Plant DOCKET I2) 05000244 LER NUMBER I6)
BEOIIEIItIAE REVISIOM ItlJMBER IIUMBER 1998
003 02 PAGE I3) 8 OF 9
TEXT fi!more spaceis required, use additional copies of NRC Form 366Ai l17)
Based on the above, it can be concluded that the plant operated as designed, that there were no unreviewed safety questions, and that the public's health and safety was assured at all times.
V.
CORRECTIVE ACTION
A.
ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMALSTATUS:
After the Control Room Radiation Monitors decreased below their alarm setpoints, the GREATS actuation signal was reset, and normal ventilation was restored to the Control Room, when appropriate.
Because the alarms were originally attributed to elevated levels of Radon and Radon decay products, the setpoints of R-37 and R-38 were calculated to be excessively conservative.
These setpoints were increased, but are still conservative.
Contributing factors to the CREATS actuations, which were due to spiking on these radiation monitors, have been addressed by the following actions:
R-36 and R-37 had degraded detector cables.
In 1991, the vendor modified the detector and cables.
The vendor manuals did not clearly identify the modification.
When the replacement detector cables were compared to the installed detector cables, the discrepancy was identified. A Vendor Technical Document change was issued to update the vendor manuals.
b.
The grounded R-37 detector and the damaged R-37 detector cable have been replaced.
C.
d.
The damaged insulation on the power supply cable has been replaced.
The 120 VAC wiring to the skid had degraded insulation.
The wiring was replaced.
The AC ripple on the high voltage power supplies for R-36 and R-37 exceeded the vendor specifications.
This AC ripple contributed to,the noise induced into the detector signaI.
The power supplies were rebuilt and/or replaced.
The skid was responding to high impedance high frequency signals being generated from switches and coils located in the vicinity of the detectors and drawers.
The monitors were responding to the false signals and actuating GREATS.
The skid was modified to install noise suppressors.(9 1999)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION U.S. NUCLEAR REGULATORY COMMISSION FACILITYNAME (1)
R.E. Ginna Nuclear Power Plant DOCKET (2) 05000244 LER NUMBER (6)
SEGUENTML REVISION NUMBER NUMBER 1998
003 02 PAGE (3) 9 OF 9
TEXT iifmore spaceis required, use additional copies of NRC Form 366AJ (17)
B.
ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:
As part of the preparation of the quarterly report for the Maintenance Rule, the System Engineer will review the signal pattern of the Control Room Radiation Monitors to identify adverse trends or increases in noise levels.
Appropriate corrective actions will be initiated if adverse trends are identified.
o Monitoring of the equipment's performance since the corrective actions have been completed has demonstrated that the equipment is still susceptible to noise spikes on a periodic basis.
As a result it has been decided to replace the equipment with newer, more reliable equipment, that is less susceptible to noise spikes.
A Technical Specification amendment request is presently being prepared.
The system upgrade will be performed following NRC approval of the Technical Specification amendment.
VI~
ADDITIONALINFORMATION:
A.
FAILED COMPONENTS:
The failed components included the Control Room Radiation Monitor detectors tfailed due to being grounded).
There were degraded detector cables, degraded solder on ribbon cable connectors and printed circuit boards, and the AC power wires had degraded insulation.
The high voltage power supplies had excessive AC ripple. The digital equipment was responding to electro-magnetic interference generated from relays and motor starters on the skid.
These components were manufactured by or supplied by Nuclear Research Corporation.
The R-36 noble gas sampler is Model No. MG-4T. The R-37 particulate sampler is Model No. MA-1BT. The iodine sampler is Model No. SA-60T.
Each sampler utilizes a DRM-200 ratemeter.
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.
SPECIAL COMMENTS:
Until 1998, Ginna Station did not consider the GREATS 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.
P Individuals recall that, prior to 1998, there were some GREATS 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.