Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
ACCESSION #: 9802100039
POWER REACTOR EVENT NUMBER: 33650
FACILITY: NINE MILE POINT REGION: 1 NOTIFICATION DATE: 02/04/98
UNIT: [ ] [2] [ ] STATE: NY NOTIFICATION TIME: 13:50
[ET]
RX TYPE: [1] GE-2, [2] GE-5 EVENT DATE: 02/04/98
EVENT TIME: 13:50
[EST]
NRC NOTIFIED BY: KENNO LAMPMAN LAST UPDATE DATE: 02/04/98
HQ OPS OFFICER: JOHN MacKINNON
NOTIFICATIONS
EMERGENCY CLASS: NOT APPLICABLE
10 CFR SECTION: LAURIE PELUSO RDO
CCCC 21.21 UNSPECIFIED PARAGRAPH
VERN HODGE (PCEB) NRR
UNIT SCRAM CODE RX CRIT INIT PWR INIT RX MODE CURR PWR CURR RX
MODE
2 N Y 95 POWER OPERATION 95 POWER OPERATION
EVENT TEXT
10 CFR PART 21: LOCKUP OF WESTRONICS RECORDERS DUE TO SERVO
AMPLIFIER
BOARD OVERRANGE FEATURE - THIS PROBLEM WAS CORRECTED IN THE FALL
OF 1997.
DESCRIPTION OF CONDITION:
THE DEVIATION DESCRIBED IN THE REFERENCED DEVIATION EVENT REPORTS
(DER)
AFFECTS THE FIVE SAFETY-RELATED (SR) RECORDERS. RECORDERS
2ISC*LR1623A/B
AND 2ISC*PR1623A/B WERE SUPPLIED TO GENERAL ELECTRIC (GE) BY
WESTRONICS
AS NON-SAFETY-RELATED INSTRUMENTS (NSR) AND WERE UPGRADED TO SR BY
GE
(PURCHASE ORDER/SPEC. P800A). FUEL ZONE LEVEL RECORDER 2ISC*LR1615
WAS
SUPPLIED AS SR EQUIPMENT AND IS FED FROM TRANSMITTER 2ISC*LT13B. THE
WIDE RANGE LEVEL RECORDERS 2ISC*LR1623A/B ARE FED FROM TRANSMITTERS
2ISC*LT9A/B. THE LATTER RECORDERS EACH ALSO DISPLAY VESSEL PRESSURE
ON A
SECOND CHANNEL AND PEN. THE PRESSURE CHANNELS 2ISC*PR1623A/B ARE
FED
FROM PRESSURE TRANSMITTERS 2ISC*PT16A/B. ALL OF THE AFFECTED
RECORDERS
ARE ON MAIN CONTROL ROOM PANEL 2CEC*PNL601. ALL OF THESE RECORDERS
ARE
SR TECHNICAL SPECIFICATIONS POST-ACCIDENT MONITORING INSTRUMENTS.
THEY
ARE IDENTIFIED ON THE NMP2 MASTER EQUIPMENT LIST AS REGULATORY
GUIDE 1.97
MONITORING EQUIPMENT. ALL OF THE ABOVE MENTIONED RECORDERS WERE
INSTALLED WHEN THE PLANT WAS INITIALLY LICENSED.
DERs 2-97-1662 AND 2-97-3030 DESCRIBE FAILURES OF THE AFFECTED VESSEL
PRESSURE AND LEVEL RECORDERS LISTED ABOVE SUCH THAT THE AFFECTED
RECORDER
CHANNEL LOCKS UP TEMPORARILY UNDER CONDITIONS WHERE THEY
EXPERIENCE A
LARGE STEP CHANGE IN THE PROCESS VARIABLE MONITORED OR WHEN THE
RECORDERS
HAVE THE PEN MANUALLY MOVED FROM THE POSITION TO WHICH IT WAS
DRIVEN BY
THE SERVO AMPLIFIER BOARD (WESTRONICS PART NUMBER B100124N04).
(Continued on next page)
FACILITY: NINE MILE POINT PAGE # 2 OF EVENT NUMBER: 33650
ALL OF THE POTENTIALLY AFFECTED RECORDERS NOW ARE (AS OF THE FALL OF
1997) NOW EQUIPPED WITH THE NEWER SERVO AMPLIFIER BOARDS. THESE
BOARDS
HAVE AN INHERENT TIME DELAY THAT ALLOWS THE BOARD TO FUNCTION
UNDER
TRANSIENT CONDITIONS WITHOUT LOCKING UP. THERE HAVE BEEN NO
FURTHER
FAILURES (OF THE TYPE DESCRIBED) EXPERIENCED SINCE THE INSTALLATION
OF
THE NEW BOARDS. THEREFORE, NO FURTHER MAINTENANCE ACTION IS
REQUIRED
WITH RESPECT TO THESE RECORDERS.
PROCUREMENT PERSONNEL HAVE VERIFIED THAT NONE OF THE OLDER MODEL
BOARDS
ARE BEING UTILIZED AT NINE MILE POINT UNIT 1 OR ARE BEING MAINTAINED AS
SPARES.
NIAGARA
MOHAWK
NINE MILE POINT NUCLEAR STATION
P.O. BOX 63, LYCOMING, NEW YORK 13093
FAX COVER LETTER
NINE MILE POINT UNIT 2
FROM: FAX TELEPHONE NUMBER: (315) 349-1400
NAME:
DEPARTMENT: LICENSING/ENVIRONMENTAL
TELEPHONE NUMBER:
FAX #
TO:
TOTAL NUMBER OF PAGES FAXED (INCLUDING COVER LETTER):
DATE: TIME:
MESSAGE:
INITIAL PART 21 NOTIFICATION
PLANT: Nine Mile Point Unit 2
TITLE: Lockup of Westronics Recorders due to Servo Amplifier Board
Overrange Feature
DESCRIPTION OF CONDITION:
The deviation described in the referenced DERs affects the five safety
related (SR) recorders. Recorders 2ISC*LR1623A/B and 2ISC*PR1623A/B were
supplied to GE by Westronics as non-safety related instruments (NSR), and
were upgraded to SR by GE (Purchase Order/Spec. P800A). Fuel zone level
recorder 2ISC*LR1615 was supplied as SR equipment and is fed from
transmitter 2ISC*LT13B. The wide range level recorders 2ISC*LR1623A/B
are fed from transmitters 2ISC*LT9A/B. The latter recorders each also
display vessel pressure on a second channel and pen. The pressure
channels 2ISC*PR1623A/B are fed from pressure transmitters 2ISC*PT6A/B.
All the affected recorders are on main control room panel 2CEC*PNL601.
All of these recorders are SR Technical Specifications post-accident
monitoring instruments. They are identified on the NMP2 master equipment
list as RG 1.97 monitoring equipment.
DERs 2-97-1662 and 2-97-3030 describe failures of the affected vessel
pressure and level recorders listed above such that the affected recorder
channel locks up temporarily under conditions where they experience a
large step change in the process variable monitored, or when the
recorders have the pen manually moved from the position to which it was
driven by the servo amplifier board (Westronics part number CB100124N04).
These failures have been identified several times by I&C,and have been
temporarily resolved by resetting the power to the recorder or
recalibrating the recorder. A newer revision of the same servo amplifier
board from Westronics, part no. CB100124N04 (symbol # 93-23-345) has
eliminated the problem. Although the newer boards have the same part
number, they may be recognized by different potentiometer identification
numbers. NMP2 has now installed the newer boards in the potentially
affected recorders (see table below; AFFECTED EQUIPMENT). However, with
the older servo amplifier boards, the affected recorders could give
readings that are grossly inaccurate due to the pens locking up.
TABLE: AFFECTED EQUIPMENT
2ISC*LR1615 Vessel level, Fuel Zone, -165 to 35 in. (single pen)
2ISC*LR1623A Vessel level, Wide Range, -5 to 205 in. (pen 1/red)
2ISC*LR1623B Vessel level, Wide Range, -5 to 205 in. (pen 1/red)
2ISC*PR1623A Vessel pressure 0-1500 psi. (pen 2/blue)
2ISC*PR1623B Vessel pressure 0-1500 psi, (pen 2/blue)
Although originally supplied SR with an upgraded servo amplifier board,
recorder 2ISC*LR1615 could have at one time been refitted with the old
servo amplifier board during subsequent maintenance activities. The
remainder of the subject recorders were originally supplied with the old
model boards already installed.
EVALUATION:
Each recorder has one servo amplifier board per channel. Any single
servo amplifier board may lock-up the affected channel (pressure or
level) under a large step change condition. There are no alarms or
interlocks generated by the recorders or the internal auxiliary switches.
2ISC*LR1615 uses no internal adjustable auxiliary switches with
setpoints. The other recorders listed above have internal switches with
high pressure/low level setpoints, but they are only used to switch the
recorder to high speed during the abnormal condition. They generate no
interlocks or alarms.
The subject recorders are primary monitoring devices for the operators
for post-accident monitoring of the vessel level and pressure, and the
instruments are used by them in the conduct of EOP actions. These are SR
QA Cat I instruments. The fuel zone level loop has an alternate SR
indicator on 2CEC*PNL601, which is 2ISC*LI13A (Div. I). There is an
analog computer point ISCLA101 covering the same fuel zone vessel water
level which would operate independent of the recorder, but it is NSR.
The subject wide range level loops have no associated analog computer
points. Alternate wide range level indications fed from the same loops
are available on the trip unit indicators on control room panels
2CEC*PNL629 and 2CEC*PNL6l8. The trip units are SR, but the indicators
are smaller and the location is less convenient for operator reference.
The subject vessel pressure loops have associated analog computer points
ISCPA100 and ISCPA101 which are independent of the recorder problems, but
they are NSR. All of the above pressure and level ranges are also
available on the Safety Parameter Display System.
Recorder 2ISC*LR1615 is a RG 1.97 Category 1 Type A instrument. It is
the only RG 1.97 fuel zone water level instrument on Division II.
Recorders 2ISC*LR1623A (Division 1) and 2ISC*LR1623B (Division II) are
the only RG 1.97 Category 1 Type A & B instruments monitoring wide range
reactor vessel water level. Recorders 2ISC*PR1623A (Division 1) and
2ISC*PR1623B (Division II) are the only RG 1.97 Category 1 Type A, B, & C
instruments monitoring reactor vessel pressure.
As Technical Specification RG 1.97 (Category 1 Type A) post-accident
monitoring equipment, the affected recorders are extensively relied upon
by operators during an accident condition. The defect described in DER
2-97-3030 is caused by an internal manufacturer's servo amplifier board
design which may lock up any affected channel (pressure or level) under
conditions involving a large step change. For this reason, the
possibility of failure of any of these recorders due to lockup of the
indication could present a significant safety hazard as described by
10CFR21.
RECOMMENDED CORRECTIVE ACTION (IF REPORTABLE):
All of the potentially affected recorders now are equipped with the newer
servo amplifier boards. These boards have an inherent time delay that
allows the board to function under transient conditions without locking
up. No further failures of the type described have been experienced
since the installation of the new boards. Therefore, no further
maintenance action is required with respect to these recorders.
Procurement has verified that none of the older model boards are being
utilized at Nine Mile Point Unit 1 or maintained as spares.
Since the older model boards have been replaced, the affected instruments
are operable at this time. GE Company (Mr. Richard Bodily) has been
informed of NMPC's intent to report this defect under 10CFR21.
*** END OF DOCUMENT ***
