05000293/LER-1987-001, :on 870112,seven Relays in safety-related Sys Determined Not Seismically Qualified for Application.Cause Not Stated.Affected Circuits Will Be Modified & Relays Replaced W/Qualified Type
| ML20211A168 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 02/11/1987 |
| From: | Lunn B, Lydon J BOSTON EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 87-022, 87-22, LER-87-001, LER-87-1, NUDOCS 8702190105 | |
| Download: ML20211A168 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| 2931987001R00 - NRC Website | |
text
'
N Fate 304 U.S. NUCLEAA 5.EluLATORY COMMISSION APPROVED OM) NO. 3160 4 104 LICENSEE EVENT REPORT (LER)
EXPIRES, S/31/88 FACILITY NAME (Il DOCKET NUMBER (2)
PAGE138 Pilarim Nuclear Power Station Unit No. 1 0 l5 I o [o l 01219I3 1loFl0l3 TITLE tel bbn-Seismically Qualified HGA Relays EVEfeT DATE (5)
LER NUMSER ($1 REPORT DATE (7)
OTHER F ACILIT1ES INVOLVED (Si IE MONTH DAY YEAR YEAR u'",
MONTH DAY YEAR F ACILITY NAMES DOCKET NUMBERIS) n 0l5l010l0g ; l 0l1 1l2 87 8 l7
~
0l0l1
~
0 l0 0l2 1 l1 8l7 o isto go ici l ;
THl3 REPORT IS WSMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR {: (ChecA one er more of the fo/foning) (11)
OPE R ATING MwEm N
,... i,,)
a,
,, mien,n,,,
,3,,,,,)
20.40 i.imm so mwim X
50nwH2H i 78mm g
w.:
0iOIO 20 40 wmm so.mwH2i sonwH2H.,
Oj,HE g$ggy,,,,,
20.406(sH1 Hell 50.73(aH2Hil 6032(aH2HvuiHA)
J66A1 20.406taH1H4v) 50.731aH2He) 60.73IsH2HvehHS) 20.40s aH11M 50.73teH2)l6HI 60331sH2Hal LICENSEE CONTACT FOR TH18 LER (12)
NAME TELEPHONE NUMBER ARE A CODE Brian P. Innn - Plant Engineer Ext. 8241 6 l1]7 7; 4 l6 l-l 7 9 l 0 0 1
1 COMPLETE ONE LINE FOR EACH COMPONENT F AILURE DESCRISED IN THl3 REPORT E13)
CAUSE
SYSTE M COMPONENT CALISE SYST E M COMPONENT G080 N
BM lR i L;Y B
B]J lRIL l Y G l 018 l0 N
B I i i I
B BIN lRlLlY G I 0l 8 l0 N
[
l l l l l l SUPPLEMENTAL REPORT EXPECTED (14)
MONTH DAY YEAR YES lif ven. compoete EXPECTED $UBhtIS$10N OA TED NO l
l l
ASSTLACT ILimot to 1400 soecer. I e, nopronometely 9,9 teen engte space typewestren tunesi (161 On January 12, 1987, the Pilgrim Nuclear Power Station was in a cold condition with the mode switch in refuel when it was determined that seven relays in safety related systems are not seismically quallfled for their application.
The problem identified was of General Electric type HGA relays with normally closed contacts (when de-energized), which open or chatter when subjected to l
less than a 0.5 g forcing function. The relays will function properly l
following a postulated seismic event however may not during the event.
The potential impact of this problem exists only when a seismic event occurs coinciG nt with a safety related function of the normally closed contacts.
A safety evaluation has been performed which demonstrates continued safe operation while the plant remains shutdown and depressurized. Corrective actions will include modifications to the affected circuits and or replacement of the relays with a qualified type.
The plant will remain shutdown pending completion of these modifications.
h190105sf0hk Z 1 s
ADocg 05 L N PDR i
i
- .s1--
,a LICENSEE EVENT REPORT (LER) TEXT CONTINUATION umovfo ous No siso-oio.
EXPCES: 8/3i/SB FACILIYY NAME (1)
DOCKET NUMBER (2)
LER NUMBER (6)
PAGE(3)
SEQvtNTI AL AE V 4eO N vgAR Pilgrim Nuclear Power Station Unit No. 1 ol5jol0l0l21913 81 7
-- 0l0l1 010 0l2 0F 0l3 On January 12, 1987, the Pilgrim Nuclear Power Station (PNPS) was in a cold shutdown condition with the moue switch in " Refuel", when it was determined that seven relays used in safety related systems are not seismically qualified for their application.
In October 1986, PNPS was notified by the Senior Resident NRC Inspector of problems identified at another nuclear plant.
The issue raised was the seismic qualification of HGA relays used in Class IE safety related applications.
In response to this concern, a review of the use of this type of relay at PNPS was initiated. Approximately 250 HGA relays in safety and non-safety systems were reviewed and resulted in an initial determination that seven relays have the potential of rendering certain systems inoperable.
These systems are High Pressure Coolant Injection (HPCI), Reactor Core Isolation Cooling (RCIC), and Core Spray (CS)(EIIS Codes BJ, BN and BM).
The deficiency identified was for normally closed contacts of HGA relays (in the de-energized mode). When subjected to a forcing function of less than 0.59, a motion similar to that of a postulated seismic event, these normally closed contacts were determined to sometimes chatter (opening and closing).
Therefore during a seismic event the relays may not function properly.
However, following a seismic event the relays function would be restored.
The seven relays which initially have been determined to have a potential for rendering their associated systems inoperable are:
Relay Nos. 14A-K20A and 14A-K20B These relays are used to allow manual bypass of the automatic opening signal to the Core Spray injection valves 1400-25A and 1400-258.
Relay Nos. 13A-K8 and 13A-K28 These relays are used to reset the Reactor Core Isolation Cooling automatic isolation relays.
The isolation relays are used to trip the RCIC turbine, close the steam isolation valves to the RCIC turbine, and provide indication to the operations staff.
Relay Nos. 23A-K32 and 23A-K33 These relays are used to reset the High Pressure Coolant Injection system automatic isolation relays.
The isolation relays are used to trip the HPCI turbine, close the steam isolation valves to the HPCI turbine, close the suction valves from the torus to the HPCI pump, close the drainpot isolation valves and to provide indication to the operations staff.
Relay No. 23A-K42 This relay closes certain steam drain isolation valves when the High Pressure Coolant Injection system is started.
- .c,o.
u.A
l LICENSEE EVENT REPORT (LER) TEXT CONTINUATION maono ows No siso-oto4 EXPIRES: 8/31/08 7 ActuTV NAME {1)
DOCKET NUMSER (2)
"UEa
O eU Pilgrim Nuclear Power Station 0151010 l o 12 l 913 817 010l1 0l0 0 l3 oF 0 l3 TEXT (# more asses a segueser, ese addeonst NMC Form JUECs/ (17)
- - The issue of HGA relay seismic qualification was raised in a July 20, 1983 letter from General Electric (GE).
This notification was in the form of a Service Advice Letter (SAL), number 721-PSM-174.1.
Historically, SAL's have identified non-safety related issues, and not concerns with potential impact on plant operability.
As such, they had been determined inappropriate as input into programs which address industry identified problems. Upon identification of SAL 721-PSM-174.1 in October, prompt action was initiated to review the concerns it identified and the Site Manager was informed of the possible safety related implications of the SAL.
At the time this condition was under evaluation and determined to effect PNPS, the plant remained in cold condition.
To immediately address the potential impact of the postulated failures on the plant, a safety evaluation was performed. This evaluation determined that the only potential impact for the existing plant condition is in the core spray system, which is designed to supply low pressure water injection for emergency core cooling, as described in PNPS Final Safety Analysis Report section 6.3.
In the event a design basis accident were to occur, with a coincident seismic event, the potential exists for the relay contacts described above to cnatter, damaging or otherwise interfering with the proper operation of the core spray injection valves.
In the worst case, the valve motor operators are postulated to fail due to overheating from repeated starts in a short period of time.
This concern is being addressed by a re-alignment of the core spray system which obviates the need for the effected HGA relay contacts to perform a safety function.
To address the RCIC and HPCI system concerns, the plant has been restricted to cold, de-pressurized conditions.
These two systems provide no safety function with the plant in this condition.
Prior to removing these administrative operating restrictions, modifications to the affected circuits will be made to address the seismic concern and assure continued system operability.
While no actual failures have occurred,.the appropriate component failure
~
information has been provided in section (13) above, as described in NUREG 1022.
The review and evaluation of all HGA relays used in safety related systems continues. The long term corrective actions which will resolve this issue are currently in review.
They will include replacement of the relays with a qualified type and or modification of circuits which are potentially affected to assure their continued seismic qualification and capability.
The potential need to review GE issued SAL's is also being examined.
.}O e;,
O Executive Ofhces 800 Boylston street Boston, Massachusetts 02199 February 11, 1987 James M. Lydon BECo Ltr. #87- 022 Chief Operating Officer U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.
20555 Docket No. 50-293 License No. DPR-35
Dear Sir:
The attached Licensee Event Report 87-001-00 "Non-Seismically Quallfled HGA Relays" is hereby submitted in accordance with the requirements of 10CFR50.73.
If there are any questions on this subject, please do not hesitate to contact me.
Respectfully submitted, N
A~
gw J
s M. Lydon BPL/la
Enclosure:
LER 87-001-00 cc: Dr. Thomas E. Murley Regional Administrator, Region i U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 Standard BECo LER Distribution cc: Dr. M. McBride h@
\\
$\\