ML17256A698
| ML17256A698 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 05/26/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17256A697 | List: |
| References | |
| NUDOCS 8305270071 | |
| Download: ML17256A698 (5) | |
Text
UNITED STATES NUC EAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE. OFFICE OF NUCLEAR REACTOR REGULATION Oe ROCHESTER GAS AND ELECTRIC CORPORATION R.
E.
GINNA NUCLEAR POWER PLANT DOCKET NO. 50-244 1.0 IHTRODUCTIOH
'he..unmonitored release pathway for ai.rborne radioactive materials.
from the R.
E. Ginna Nuclear Power Plant to the environment during the steam generator tube rupture incident involved two effluent radio-activi ty monitoring systems:
(1)
The main steam radiation monitoring system, which is designed to
- detect, indicate,
- record, alarm, and quantify radioactive materials released from the steam generator PORVs and safety valves; and (2)
The air ejector radiation monitoring system, which is designed to
- detect, i ndi cate,
- record, alarm, and quantify releases of radio-active materials in noncondensible gases released from the secondary system steam via the air ejector and turbine gland seal exhaust.
During the incident, a high radiation alarm setting for the main steam radiation monitoring system was not reached and this prevented the system from activating the recorders.
Later..attempts to retrieve the data from the monitoring data processing system also failed due to a malfunction of the monitor during the incident.
The licensee stated in his incident evaluation report that the monitor malfunction is believed to have been due to a small smudge of dirt or residue which caused electrical leakage on a printed circuit board.
In addition, the steam generator PORV and safety valve position monitoring function failed during the incident.
The licensee states that inadequate adjustment of the new actuator rods installed on the safety valves, and open sliding links on terminal blocks in the relay room for the
- PORV, caused the inoperability of the valve posi tion moni tor.
For the air ejector radiation monitoring system, the SPING R-15A low range
~
monitor actuated a high radiation alarm during the incident, and was suspected of having been off scale after activating the SPING R-15A middle range monitor.
However, while the low range monitor was off
- scale, no 10-minute average radiation readouts or recordings were ob-tained from the SPIHG R-15A middle range monitor because its high alarm setpoint was not reached and this prevented the system from activating
, the re'corder.
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Subsequent to the incident, the licensee made corrections on alarm setpoints for both main steam and air ejector effluent radiation monitors.
Therefode, the staff had no safety concerns prior to Ginna restart;
- however, the staff stated in the Ginna Restart SER (NUREG-0916) that it would review and evaluate the licensee's corrective actions for both main steam and air ejector radiation moni toring systems.
2.0 EVALUATION
- 2. 1 i<gin Steam Radiation Yionitorin S stem The staff reviewed
( 1) the adequacy and basis of the monitor high alarm setpoi nts, (2) the monitor operability surveillance
- program,
., (3) the moni tor ranges and sensi.tivity with. respect to their capability to cover accident conditions, and (4) procedures or calculative methods to be used for converting monitor readings to release rate per unit time.
Subsequent to the incident, the alarm setpoint was lowered to 0.1 mR/hr from 1.0 mR/hr.
The alarm setpoint of 0.1 mR/hr is just above ambient background radiation levels to provide maximum sensitivity while preventing spurious alarms.
The monitoring system consists of a collimated energy-compensated Geiger-llueller detector (Eberline t1odel SA-11) on each main steam
- line, and the 0.1 mR/hr alarm setpoint is calibrated to a radio-activity concentration of 0.01 uCi/cc (Xe-133) in main steam.
The 3
4 monitor has a maximum range of 10 uCi/cc (10 mR/hr) which is consistent with ihe requirements specified in NUREG-0737 (Item II.F.l, ).
The monitor is capable of functioning'both during and following a design-bases accident..
The system indicates radioactivity readouts locally, and in the. main control room and Technical Support Center (TSC).
An audible alarm sounds locally and in the main control room.
The monitor system can be programmed to automatically print radioactivity concentrations in main steam for the last 24 hourly averages once a day and the last 23 ten minute averages every four hours.
In the demand
- mode, the last 24 daily averages, the last 24 hourly averages, the last 23 ten minute
. averages, and the current value for radioactivity concentration (uCi/cc) and/or release rate (uCi/sec) can be printed.
The system is functionally test'ed quarterly in accordance with Ginna Test Procedure TP-17.3, Rev.
10, dated September 9, 1982.
Activation of recorders for radiation level, as well as safety valve and atmospheric steam dump valve positions, are verified on receipt of a high alarm signal by the portable source.
Subsequent to the incident, the licensee had (1) lowered the alarm setpoint, (2) inspected and replaced the af-fected monitor printed ci rucit boards which caused monitor malfunction, (3) readjusted actuator rods'installed on the safety valves which caused
the inoperability'f the valve position monitoring, and (4) implemented operati onal surveillance test procedures.
Based on staff observation of the monitors in operation, its 'review of the licensee's calibmtion and test procedures, consistency with the requirements specified in NUREG-0737, and corrective actions taken by the licensee subsequent to the incident, the staff concludes that the main steam radiation monitoring system is acceptable.
2.2 Air Ejector Radiation Monitorin S stem The staff reviewed (1) the adequacy of readouts and recording capability, (2) the adequacy of all monitor alarm setpoints, (3) the monitor operability surveillance
- program, (4) the procedures or calculative methods to be used for converting the moni'tor readouts to release rate per unit, time,
=and (5) the need to provide. a contin-uous and instantaneous indicator-recorder (strip chart), in addition to the 10-minute average readouts in the computer to indicate release rate of airborne radioactive materials from the air ejector exhaust to the environment.
The system consi sts of two radiation monitors:
the R-15 monitor and the SPIHG R-15A monitor.
The R-15 monitor is a sodium iodine detector (Yictoreen Model Ho. 843-03) mounted on the outside of the 8-inch 2
6 diameter exhaust pipe and has a range of 10 to 10 cpm gamma radia-tion (equivalent to 0 to 0.1 uCi/cc).
The response of this monitor is recorded on a strip chart and also fed to a computer.
During the incident, ihe strip chart recorder for the R-15 monitor went off scale.
The SPIHG R-15A monitor (Eberline tiodel SPIHG-4) is a high range monitor and has three sensitivi ty ranges with a separate detector for each range.
Range Low Detector beta scintillation High compensated GM tube Middle compensated GN tube
- Range, uCi/cc 10 to 0.05 2.8 x 10 to 10 0.03 to 10 5 Alarm Setpoint, uCi/cc 2x10 2x10 Subsequent to the incident, the high range monitor (R-15A) alert and high alarms for low, middle and high range channels have been reset to correspond to a percentage of the plant release rate limit and have been specified in Ginna Operating Procedure P-9, Rev. 33, 'Radiation Monitoring System'ated January 18, 1983.
Setpoints are preset so that an alarm is activated by a higher range monitor before the lower range monitor goes offscale.
In addition, the lowest range monitor of R-15A will alarm
~
before..R-15 reaches full scale.
The high range monitor (R-15A) readout, recording and alarm capabilities and progammabilities are identical to those of the main steam radiation monitors.
In addition, the monitor readouts are automatically printed every 10 minutes.-in the control room and TSC, if any R-15A channel reaches a high alarm condition awhile the alarm condition exists.
Both monitor operability surveillance programs require (1) daily channel
- check, (2) monthly source
- check, (3) quarterly functional test, and (f) annual channel calibration.
The monitor operating procedures and calculative methods to be used for converting the monitor readouts to release rates are described in Ginna Operating Procedure PC-23.5, Rev.
1, dated March 2, 1983.
Since neither instantaneous meteorology parameters nor release rates are used for ac-cidentt dose calculations, a strip chart recorder, i n addition to the 10-
.minute average readouts
.in the computer, isnot needed.for the high range monitor.
Based on its observation of the monitors in operation; its review of the licensee's operational, calibration, and test procedures; consistency with the requirements specified in HUREG-0737 and Standard Review Plan Section 11.5; and corrective actions taken by the licensee subsequent to the incident, the staff concludes that the air ejector radiation monitors (R-15 and R-15A) are acceptable.
3.0 COHCLUSIOHS Based on the foregoing evaluation, the staff concludes that, the corrective actions taken by the licensee subsequent to the steam generator tube rup-ture incident are adequate and that the main steam and air ejector radiation monitoring systems in operation are acceptable.
The basis for staff acceptance has been
( 1) conformance of the systems to the require-ments specified in HUREG-0737
( Item LI.F.1, Attachment
- 1) and Standard Review Plan Section 11.5, (2) observation of the monitoring systems in operation, (3) satisfactory revi ew of Ginna operating and calibration procedures for the monitoring systems, and (4) adequate monitor alarm setpoi nts and satisfactory operational surveillance requirements.
l 4.0 ACKHOMLEDGEt'lEHT Jay Lee prepared this evaluation.
Date:
Hay 26, 1983