ML20107D251
Text
_
(?
To:
James P. O'Reilly Directorato of Regulatory Operatiorts Region i 631 Park Avenue King of Prussia, Pennsylvania 19406 From:
Jersey Central Power 6 Light Cor:pany Oyster Creek Nuclear Generating Station Docket #50 219 Forked River, New Jersey 08731
Subject:
Abnormal Occurrence Poport No. 50 219/74/ 9 The following is a preliminary report belh2 subudtted in compliance with the Technical specifications paragraph 6,6,2, Preliminary Approval:
/
[M.,_jd 2/1/74 A
kJ. T. Carroll, Jr. M Date cc Mr A. Gianbusso 9604180188 960213 PDR FOIA DEKOK95-258 PDR
initial Written Time cf Report Dato:
2/1/78 Occurztnce:
1320 OYSTER CREEK NUCLEAR GENERATING STATION
' PORKED RIVER, NEW JERSI!Y 08731 Abnormal Occurrence Report No. $0-239/74/ 9" IDPETIFICATION Violation of the Technical Specifications, paragraph
- 2. 3. 7, OP OCCURRENCE:
Low Ptchsure Miin Steau Line Pressure Switches (PE23A and D) woro found to trip at pressures less than the specified value (850 psig and 10 psig head correction factor).
'This CVent is con $idered to be an abnormal occurrence as de.
fined in the Technical Specifications, paragraph 1.15A CONDITIONS PRIOR l
TC OCCURRENCE:
X Steady State Power Routine Shutdown Hot Standby
_ Operation Cold Shutdown Load Changes During Refueling Shutdown
~ Routine Power Operation Routine Startup Other (Specify)
Operation The msjor plant parameters at the time of the event were as follows:
Pgwer - Core, 1902.9 !#t Flow - Recirc., 75.9x10lg)
!?lec., 669 We lb/hr Pced., 7.2x10' #/hr Stack Gas - 23,250 PCl/$ec, l
DESCRIPTION On Thursday, January 31,1974, at 1320, while perforrning routine OF OCCURRENCE:
surveillance testing on the four Hain Steam Line Low Pressurc Switches, it was discovered that RE23A and RE23D tripped at 858 psig and 856 psig, respectively.
This was 2 psig and 4 psig below tie setpoint of 860 psig, Although the Technical Speci ff-cations call for a Main Stoam Line low pressure sotpoint of 850 psig, the sotpoint for the switches is 860 psig to account for the difference in head between t.he switches and the Main Steam Li nc.
e O i~,
^
ff=
~~ "
W; port ho,1u.21w/4/1 ^
^ ^ ~
~
y
~
)
)
~
As t'ound switch settings were:
Teat #1 Test #2 RU23A 860 psig 858 P812 RE23B 860 psig 860 psig RH23C 863 psig 862 psig RE23D 856 psig 856 psig i
Repeatability of the sensors was checked by observing two con-secutive trip points.
1
%e pressure switches were then recalibrated and checked to actuate as follows Test #1 Test #2 i
RE23A 861 psig 861 psig RE23D 862 psig 861 psig APPARE)TT CAUSB X
Design Procedurc OP OCCURRDNCB:
Manufacturc X
Unusual Servico Condition Installation /
Inc. Environmental
~ Can.,tructi on Component Failure Operator
_ Other (Speci fy) l l
Sensor drift is a recognized problem and work is in progress to formulate a final solution.
The steps required to achieve this end wore delineated in Abnormal Occurrence Report No. 73-30.
ANALYSIS OF As indicated in the bases of the Technical Specification, "The OCCl)RRENCE :
low pressure isolation of the Main Stosm Lines et 8$0 psig was provided to give protection 32hinst fast reactor depressurlastion and the resultant rapid cocidown of the vessel, Advantage Was taken of the scram feature which occurs when the Main Steam iso-lation Valves are closed to provide for reactor shutdown so that high power operation at low reactor pressure does not occur, thus providing protection for the fuel cladding integrity e,sfety limit."
eng_ _
i snorma rvccunvnvo--
R0 port Noo 50-219/74/ 9 Page 3
$l I
a The adverse consequence.$ of reactor isolation occurring "at
)
roactor pressure approximately 4 psi below the specifico minimum value of 860 psig is limited to those effect's attendant to a J
greater than normal reactor coolduvn rate. The fuel cladding integrity safety limit only comes into effect for power opera-tion at reactor pressures Ics's fhan 600 psig or for power opera-
~
tion greater than 354 HWt with less than 10% recirculation flow.
Therefore, the consequences bf a 4 psi Iwer than normal reactor isolation and scram setpoint has no threatening effect whatso-ever on the fuel cladding integrity.
The effects of a too rapid couldown due to the lower isolation pressure
. art inconsequential since there is lesA than l'F difference between the saturation temperature for 860 p$ig and 856 psig, The adverse safety effect of im23A and E23D actuating at the as found pressures is in the loss of system redundancy, The other two sensors, RU23B and D, would have functioned normally, CORRIC1\\T:
Continuing corrective actions being t:d:en at this time are as AITION:
follows:
1.
Investigation is being conducted into the basis for the stenn line low pressure setting of 850 psig. Development of a Technical Specification change to lower the setpoint will fo116if.results of transient analyses indicate this possibility (soc Abnormal occurrence Report ho, 73-30).
Abnormal Occurrence -
Repot1. No, W 219/74/ } )
Page 4 es y,
L 2.
Vendor reconsendatioris to possibly reduce or eliminate the L
sensor 8etpoint' drift problem will be evaluated as soon as they are available (istter to Mr. A. Gianbusso from Mr. D. A.
Ross, dated Decenber 24, 1974),
FAILURE DATA:
Manufacturer data portinent to thscs switches are as follows:
Eletron corp. (subsidiary of Barksdale)
Los Angeles, Califomia Pressure Actuated Switd1 Nodel 172 Catalog #372-6SS49A-293 Hange 20-1400 psig Proof Pnl.1750 G Propured by: \\-
OMT Av
[..w 1,
. Dato:
2/]/74 0
l
- -