05000280/LER-1999-005-01, :on 990731,effluent Radiation Monitors Were Declared Inoperable.Caused by Degraded Heat Trace Circuits for Monitors Sample Suction Line.Degraded Heat Trace Circuit Was Replaced & Addl Heat Trace Is Being Installed
| ML18152B441 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 08/27/1999 |
| From: | Grecheck E VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | |
| Shared Package | |
| ML18152B372 | List:
|
| References | |
| LER-99-005-01, NUDOCS 9909020020 | |
| Download: ML18152B441 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 2801999005R01 - NRC Website | |
text
e NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB NO. 3150-0104 EXPIRES 06/30/2001 (6*1998)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
FACILITY NAME (1}
DOCKET NUMBER (2)
PAGE (3)
SURRY POWER STATION, Unit 1 05000-280 1 OF 4 TITLE(4)
Radiation Monitors Inoperable Due to Heat Trace Failure EVENT DATE (5)
LER NUMBER 6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED (8)
I SEQUENTIAL REVISION FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NUMBER MONTH DAY YEAR Surry Power Station, Unit 2 05000 -- 281 1999 005 00 FACILITY NAME DOCKET NUMBER 07 31 1999 08 27 1999 05000 --
OPERATING N
THIS REPORT IS SUBMITIED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check one or more) (11)
MODE (9) 20.2201(b) 20.2203(a)(2)(v)
- 50. 73(a)(2)(i)
- 50. 73(a)(2)(viii)
POWER 100%
20.2203(a)(1) 20.2203(a)(3)(i)
- 50. 73(a)(2)(ii)
- 50. 73(a)(2)(x)
LEVEL (10) 20.2203(a)(2)(i) 20.2203(a)(3)(ii) 50.73(a)(2)(iii) 73.71 r?:'.. "'\\ti:<
01, <.
20.2203(a)(2)(ii) 20.2203(a)(4)
- 50. 73(a)(2)(iv)
X OTHER f.,?;/ f j(,.,.\\(: */i(J 20.2203(a)(2)(iii) 50.36(c)(1) 50.73(a)(2)(v)
Specify in Abstract below or 20.2203(a)(2)(iv) 50.36(c)(2) 50.73(a)(2)(vii) in NRC Form 366A LICENSEE CONTACT FOR THIS LER (12)
NAME TELEPHONE NUMBER (Include Area Code)
E. S. Grecheck, Site Vice President (757) 365-2001 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
CAUSE
SYSTEM COMPONENT MANUFACTURER REPORTABLE :~f
CAUSE
SYSTEM COMPONENT MANUFACTURER REPORTABLE TO EPIX TO EPIX X
IL MON Kaman y
- .{.'.
Sciences Corp X
IL Heat Therrnon Mfg N
sf Trace Corp SUPPLEMENTAL REPORT EXPECTED (14)
EXPECTED MONTH DAY YEAR
'YES Ix INo SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE).
DATE (15)
ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)
Units 1 and 2 were operating at 100% and 82% power, respectively, on July 31, 1999, when a control room annunciator alarmed, indicating a problem with the effluent radiation monitors. The appropriate annunciator response and abnormal procedures were promptly performed and a low sample flow condition was identified for the gaseous vents system radiation monitors, 1-VG-RM-131-1 and 1-VG-RM-131-2. The monitors were declared inoperable at 08:28 and the preplanned alternate method of monitoring was initiated in accordance with Technical Specifications (TS) Table 3.7-6.
An action statement was entered in accordance with TS Table 3.7-6, requiring restoration of the monitors within seven days or the submittal of a Special Report within 30 days. Investigation of the problem revealed that one of the heat trace circuits for the monitors' sample suction line was degraded, which allowed the formation of condensation within the system. As a result, condensation accumulated and blocked the sample flow through the system. The degraded heat trace circuit was replaced, additional heat trace is being installed, and the monitors are scheduled to be returned to service by August 30, 1999. To prevent recurrence, a preventive maintenance task was initiated to periodically check the condition of the heat trace circuits. This Special Report is being submitted pursuant to TS Table 3.7-6.
9909020020 990827 0 PDR ADOCK 0500028 S
e e (6-1998)
FACILITY NAME (1)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION D0CKET(2)
SURRY POWER STATION, Unit 1 05000 -- 280 TEXT (If more space is required, use additional copies of NRG Form 366A) (17) 1.0 DESCRIPTION OF THE EVENT U.S. NUCLEAR REGULATORY COMMISSION LER NUMBER 6)
PAGE (3)
YEAR I SEQUENTIAL REVISION NUMBER NUMBER 2 OF 4 1999 -
005 --
00 Units 1 and 2 were operating at 100% and 82% power, respectively, on July 31, 1999, when control room annunciator 1-RMA-C4 [EIIS:-18) alarmed, indicating a problem with the effluent radiation monitors [EIIS-IL,MON]. The appropriate annunciator response and abnormal procedures were promptly performed and a low sample flow condition was identified for the gaseous vents system radiation monitors, 1-VG-RM-131-1 (normal range) and 1-VG-RM-131-2 (high range). As a result of this condition, 1-VG.,RM-131-1 and 1-VG-RM-131-2 were declared inop*erable at 08:28 and the preplanned alternate m*ethod of monitoring was initiated in accordance with Technical Specifications (TS)
Table 3.7-6. - An action statement was entered in accordance with TS Table 3.7-6, requiring restoration of the monitors within seven days or the submittal of a Special Report within 30 days.
During the preceding three-week period, 1-VG-RM-131-1 and 1-VG-RM-131-2 had experienced similar low sample flow conditions. l&C personnel had performed extensive troubleshooting and had replaced several components to restore the system to an operable status. Further investigation revealed that one of the heat trace circuits for the monitors' common sample suction line was degraded, which allowed the formation of condensation within the system. As a result, condensation accumulated and blocked the sample flow through the system.
The degraded heat trace circuit was replaced on August 13, 1999. However, 1-VG-RM-131-1 and 1-VG-RM-131-2 have not been returned to an operable status due.
to the difficulty in removing accumulated moisture from the system. Additional heat trace is being added to the system to further reduce moisture accumulation.
This Special Report is being submitted pursuant to TS Table 3.7-6 since 1-VG-RM-131-1 and 1-VG-HM-131-2 were not returned to an operable status within seven days.
2.0
SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS
1-VG-RM-131-1 and 1-VG-RM-131-2 are designed to survey effluents that may be released from the auxiliary building ventilation vent No. 2 following an accident. These radiation monitors are not safety-related and do not initiate any automatic equipment actuations.
e e (6-1998)
U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
D0CKET(2)
LER NUMBER 6)
PAGE (3)
YEAR I SEQUENTIAL REVISION NUMBER NUMBER SURRY POWER STATION, Unit 1 05000 -- 280 3 OF 4 1999 -
005 --
00 TEXT (If more space is required, use additional copies of NRG Form 366A) (17) 2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS (Continued)
When the subject monitors were declared inoperable, the preplanned alternate method of monitoring was initiated, utilizing auxiliary building ventilation vent No. 2 high range effluent monitor, 1-VG-RM-123. In addition, Health Physics personnel were notified that the monitors were out of service and that off-site monitoring may be necessary in the event of a radioactive release.
These compensatory measures provide an acceptable alternate method of satisfying the design functions of 1-VG-RM-131-1 and 1-VG-RM-131-2. Therefore, this event resulted in no safety consequences or significant implications and the health and safety of the public were not affected at any time.
3.0
CAUSE
The sample suction line for 1-VG-RM-131-1 and 1-VG-RM-131-2 is heat traced to preclude moisture in the gas sample from condensing. An accumulation of moisture in the system is not desirable since it could affect the accuracy of iodine and particulate sampling, and potentially impede sample flow.
This event was caused by the partial failure of one of the heat trace circuits on the sample suction line, which allowed moisture to condense within the system and block the sample flow to the monitors. This condition was exacerbated by the absence of heat trace on the radiation monitors' skid and sample discharge line.
4.0 IMMEDIATE CORRECTIVE ACTION(S)
The appropriate annunciator response and abnormal procedures were promptly performed.
1-VG-RM-131-1 and 1-VG-RM-131-2 were declared inoperable and the preplanned alternate method of monitoring was initiated.
5.0
ADDITIONAL CORRECTIVE ACTIONS
The degraded heat trace circuit was replaced and efforts are underway to remove accumulated moisture from the system. 1-VG-RM-131-1 and 1-VG-RM-131-2 are scheduled to be returned to an operable status by August 30, 1999.
e e (6-1998)
U.S. NUCLEAR REGULATORY COMMISSION FACILITY NAME (1)
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION D0CKET(2)
LEA NUMBER 6)
PAGE (3)
YEAR I SEQUENTIAL REVISION NUMBER NUMBER SURRY POWER STATION, Unit 1 05000 -- 280 4 OF 4 1999 -
005 --
00 TEXT (If more space is required, use additional copies of NRG Form 366A) (17) 6.0 ACTIONS TO PREVENT RECURRENCE A preventive maintenance task was initiated that will periodically check the condition of the heat trace circuits for 1-VG-RM-131-1 and 1-VG-RM-131-2.
To help minimize the potential for condensation within the system, heat trace is being installed on the radiation monitors' skid and sample discharge line.
7.0
SIMILAR EVENTS
Special Report No. 50-280/1994-007-00 Process Vent High Range Accident Monitor Inoperable Greater Than Seven Days 8.0 MANUFACTURER/MODEL NUMBER Kaman Science Model: HAN, HRH -- --* '**.. -;... -,.._.