05000483/LER-1994-001, :on 940427,TS 3.5.1 Violation Occurred Due to High Pressure Alarm Condition on Two Safety Injection Accumulators Resulting in TS 3.0.3 Entry.Caused by Increase in Ambient & Containment Temp.Amend Submitted
| ML20070S678 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 05/16/1994 |
| From: | Blosser J, Sharkey T UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| LER-94-001, LER-94-1, ULNRC-03019, ULNRC-3019, NUDOCS 9405240144 | |
| Download: ML20070S678 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4831994001R00 - NRC Website | |
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Callaway Plant Pcst offu Box 6?D Fuimm Mn;souri55251 UVION May 16,1994 EuzenueE U. S. Nuclear Regulatory Commission Document Control Desk j
Washington, D. C. 20555 i
ULNRC-03019 Gentlemen:
DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 i
FACILITY OPERATING LICENSE NPF-30 LICENSEE EVENT REPORT 94-001-00 TECII SPEC 3.5.1 VIOLATION DUE TO IIIGII PRESSURE ALARM CONDITION ON TWO SAFETY INJECTION ACCUMULATORS CAUSED TECll SPEC 3.0.3 ENTRY 1
The enclosed Licensee Event Report is submitted pursuant to 10CFR 50.73(a)(2)(i)(B) concerning a condition prohibited by Callaway Plant Technical Specifications.
j
- - 1 J. D. Blosser Manager, Caliaway Plant d
1 JDB/TPS/MKD/Irj Enclosure cc: Distribution attached j
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- aus, 9405240144 940516
.-PDR ADOCK 05000483 s
cc distribution for ULNRC-03019 Mr. J. B. Martin Regional Administrator U. S. Nuclear Regulatory Commission l
R:gion Ill
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301 Warrenville Road Lisle, Illinois 60532-4351 Mr. L. Raynard Wharton (2 copies)
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Licensing Project Manager j
U. S. Nuclear Regulatory Commission OWFN - Mail Stop 13E21 Washington, D. C. 20555 Manager, Electric Department Missouri Public Service Commission P. O. Box 360 Jefferson City, MO 6510~2 Records Center Institute of Nuclear Power Operations j
700 Galleria Parkway Atlanta, GA 30339 Mr; Art Mah Wolf Creek Nuclear Operating Corporation P. O. Box 41i Burlington, KS 66839 Mr. M. J. Farber Chief, Reactor Projects Section ill A U. S. Nuclear Regulatory Commission i
Region Ill i
801 Warrenville Road Lisle, Illinois 60532-4351
.1 Mr. Thomas A. Baxter-.
[
Shaw, Pittman, Potts & Trowbridge 2300 N Street N.W.
Washington, D.C. 20037 NRC Senior Resident inspector l
/
1 LICENSEE EVENT REPORT (LER)
F ACILITY NAME (1)
DOCKET NUMBER 12)
PAGE 131 l Or l 0 l4 Callaway Plant Unit 1 Olcl0l0l0 l4 l8 l3 1
Tech Spec 3.5.1 Violation Due to Iligh Pressure Alarm Condition on Two Safety Injection Accumulators Caused Tech Spec 3.0.3 Entry FVENT DATE ($1 (ER NUMBER 1R1 RE PORT DATE (7)
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LICENSEE CONTACT FOR THl$ t.ER (12)
NAME TELFPHONE NUMBEM AREA CODE Thomas P. Sharkey, Supervising Engineer, Site Licensing 3lil4 6l7l6l_l8l3l3l6 COMPLETE ONE LINE FOR EACH COMPONENT F AltuRE DESCRIBFD IN THl$ REPORT (13)
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At 1925 CDT on 4/27/94, the 'B' Safety injection (SI) accumulator high pressure alarm annunciated.
Technical Specification (T/S) 4.5.1.1 demonstrates the operability of each SI accumulater by verifying, by " absence of alarms," nitrogen cover pressure. The 'B' SI accumulator was declared inoperable and T/S 3.5.1 action (a) was entered. As the licensed reactor ormnor was preparing to vent the accumulator, the 'C' SI accumulator high pressure alarm annur.ciated at 1926. Because T/S 3.5.1 provides action only for one inoperable accumulator, T/S 3.0.3 was entered even though the actual pressure in both accumulators was lower than the high pressure of 648 psig specified in T/S 3.5.1. At 1927, the high pressure alarm on the 'C' Si accomulator was cleared. T/S 3.0.3 was exited. The plant was in Mode 1, Power Operations at 100 percent reactor power.
The high pressure in 'B' and 'C' SI accumulators is attributed to a gradual increase in ambient and
. containment temperature. Work on the 'B' train containment coolers contributed to the increase in containment temperature.
An operating license amendment was submitted, previous to this event, to change T/S 3/4.5.1 to remove the relianet an absence of alarms and allow the use of other means, such as installed instrumentation and main control board indications, to determine the operability of the Si accumulators.
s s
i LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME fil DOCKE T NUMBER (2)
L t R NUM B( R f 61 PAGE Di M SAAF NO Callaway Plant Unit 1 ol slo lolol4l8l3 9l4
- - olol1
. olo ol2 ol4 or TEXT fff more space ne required, use additional NRC Form 366A'ay17)
BASIS FOR REPORTABILITY:
On 4/27/94, from 1926 CDT to 1927, Reactor Coolant System (RCS) Safety Injection (SI)
Accumulators 'B' and 'C'(l) were inoperable due to the presence of high pressure alarms. The actual accumulator pressure did not exceed the Technical Specification (T/S) Limiting Condition for l
Operation (LCO) pressure limit of 648 psig. Ilowever, the alarms constituted a condition prohibited l
by T/S 3/4.5.1, requiring entry into T/S 3.0.3, which is reportable per 10CFR50.73(a)(2)(i)(B).
DESCRIPTION OF EVENT
The 'B' train containment coolers (2) were tagged out of service at 1332, on 4/27/94, to support handwheel replacement work on EF-ilV-0048, Essential Service Water bypass isolation valve (3) from containment coolers.
At 1925, the 'B' Si accumulator high pressure alarm annunciated. T/S 4.5.1.1 demonstrates the operability of each SI accumulator by verifying the tank nitrogen cover pressure, by " absence of alarms." On receipt of the alarm, the 'B' SI accumulator was declared inoperable and T/S 3.5.1 action (a) was entered. As the licensed reactor operator was preparing to vent the accumulator per T/S 3.5.1 and procedure OTN-EP-00001, Accumulator Safety injection System, the 'C' SI accumulator high pressure alarm annunciated at 1926. Because T/S 3.5.1 only provides action for one inoperable accumulator, T/S 3.0.3 was entered.
At 1927, the high pressure alarm on the 'C' Si accumulator was promptly cleared by venting.
T/S 3.0.3 was exited. The 'B' train containment coolers were declared operable at 2044.
PLANT CONDITIONS AT TIME OF EVENT:
Mode 1 - Power Operations 100% Reactor Power l-(.
1
r.
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME lit DOCKET NUMt4R (2l LE R NUMPFR 161 PAGEf31 TA" T
Callaway Plant Unit 1 olslololol4lala 9l4 olol1 olo ol3 ol4 or TLxT (if move space is teamed, use addersonal NRC Form 366 A's)(17)
ROOT CAUSE/ CONTRIBUTING FACTORS:
The high pressure in the 'B' and 'C' Si accumulators was the result of a gradual increase in ambient and containment temperature. Due to ambient conditions and the inoperable 'B' train containment coolers, containment temperature gradually increased from 96 to 105 degrees F during the seven hours prior to the alarms, leading to an increase in accumulator pressure from 637 to 643 psig.
CORRECTIVE ACTION TO PREVENT RECURRENCE:
An Operating License amendment was submitted on 2/17/94 to change T/S 3/4.5.1 to remove the reliance on absence of alarms and allow the use of other methods, such as installed instrumentation and control board indications, to determine operability. This will preclude a future T/S 3.0.3 entry for a similar event, since the operators had sufficient time following the alarm to verify accumulator pressure.
SAFETY SIGNIFICANCE
Each SI accumulator has two pressure channels (4). Based on a review of previous channel calibration records for 'B' and 'C' accumulator pressure transmitters (5), it was determined that the pressure bistable channels that tripped (EP-PT-962 and 964) tripped at a lower pressure setpoint than the other two pressure channels when last calibrated during a recent refuel. Since only one bistable per accumulator actuated, this indicates that actual accumulator pressure did not exceed the T/S limit of i
648 psig since the second bistable for each accumulator did not trip.
i The accumulators were inoperable only due to the presence of one high pressure alarm on each 1
accumulator. This condition would not have prevented the SI accumulators from performing their j
safety function to inject into the RCS, since accumulator pressures were within the LCO requirements. The T/S high pressure limit for the accumulator is set to prevent an accumulator tank over-pressure condition. Upon annunciation of the alarms, the licensed reactor operator took immediate action to clear the alarm condition. No plant transient occurred as the result of this situation. There was no threat to the public health and safety.
PREVIOUS OCCURRENCES
None.
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\\
LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION F ACILil f NAMF, (1)
DOCKET NJMBER (21 t ER NUMBFH #6p PAGE (3)
M EA fR NO Callaway Plant Unit 1 ol slo lolol4l8l3 9 4
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FOOTNOTES:
The system and component codes listed below are from IEEE Standards 805-1984 and 803A-1984 respectively,
- 1) System - BQ; Component - ACC
- 2) System - BK; Component - CLR
- 3) System - BI; Component - ISV
- 4) Syste.m - BQ: Component - CII A
- 5) System - BQ: Component - PT L-