05000331/LER-1994-001, :on 940107,determined That Test of APRM High Flux Scram Trip Setpoint Inadequate Due to Lack of Awareness.Surveillance Test Procedure for Testing Flow Biased APRM Scram Trip Setpoint Revised
| ML20063E795 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 02/04/1994 |
| From: | Kerr J, Denise Wilson AFFILIATION NOT ASSIGNED |
| To: | Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| LER-94-001, LER-94-1, NG-94-0323, NG-94-323, NUDOCS 9402100247 | |
| Download: ML20063E795 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(1) |
| 3311994001R00 - NRC Website | |
text
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- ES INDUSTRIES INC.
February 4, 1994 NG-94-0323 Mr. John B. Martin Regional Administrator Region III U. S. Nuclear Regulatory Commission 801 Warrenville Road Lisle, IL 60532
Subject:
Duane Arnoa argy Center Docket No:
50-331 Op. License DPR-49 Licensee Event Report #94-001 Gentlemen:
In accordance with 10 CFR 50.73 please find attached a copy of the subject Licensee Event Report.
Very truly yours,
,hwEhpklA W
David L. Wilson Plant Superintendent - Nuclear DLW/JK/eah cc:
Director of Nuclear Reactor Regulation Document Control Desk U.S. Nuclear Regulatory Commission Mail Station P1-137 Washington, D. C.
20555 NRC Resident Inspector - DAEC I
080047 9402100247 940204 PDR ADOCK 05000331 200 F r treet, S E Post Office Box 351 Cedar Rapids, Iowa 52400 319/398 4411 j ;
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DOCKET NUMBER (2)
P AGE (3)
Duane Arnold Energy Center i
05000 331 OF 4 TITLE (4)
Inadequate Test of the APRM High Flux Scram Trip Setpoint EVENT DATE (5)
LER NUMBER (6 REPORT NUMBER (7)
OTHER FACILITIES INVOLVED (8)
MONTH DAY YEAR YEAR MONTH DAY 4t.AR g
FACILrTY NAME DOCKET NUMBER 01 07 94 94 001 00 02 04 94 05000 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Cneck one or morel (11)
MODE (9)
N 20.402to) 20.405(c) 50.73(a)(2)(iv) 73.71(b)
POWER 20.405(a)(1)(i) 50.36(c)(1)
X 50.73(a)(2)(v) 73.71(c)
LEVEL (10) 100 20.405(a)(inii) 50.3stcM2) 50.73(aM2Mvn)
OTHER 20.405(a)(1)(iii)
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20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(viii)(B)
[Cs A3 20.405(a)(1)(v) 50.73(a)(2)(iii) 50.73(a)(2)(x)
LICENSEE CONTACT FOR THIS LER (12)
NAVE TELkPMONE NUMBEH (imwe Area Coce)
I John D. Kerr, Technical Support Specialist (319) 851-7492 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
CAUSE
SYS'EU COMPONE NT MANUFACTURER
CAUSE
SYSTM COMPONENT MANUFACTURER g
i SUPPLEMENTAL REPORT EXPECTED (14)
EXPECTED WM DAY 1 EAR YEs SUBMISSION P yn, comrnre EXPECTED SUBM:SSON DATE)
X DATE (15)
" ABSTRACT (Limit to 1400 spaces, t.e, approximately 15 single-spaced typewntten lines) (16) t t
On January 7, 1994 while the plant was operating at 100% power, it was i
determined that the test of the average power range monitor (APRM) high flux scram trip setpoint was inadequate. The test has not been performed at a recirculation flow greater than 100% to assure that the scram setpoint does not exceed 120% rated power, as required by the Technical Specifications.
The APRMs were considered to be inoperable and a 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> to Startup mode limiting l
condition for operation (LCO) was entered. The test was revised and performed j
with satisfactory results and the LCO was exited. This condition was caused by a lack of awareness of the requirement to test the " clamping" function on the scram trip setpoint.
The test results verified that the " clamping" function had been and is set properly. There was no effect on safe operation of the plant.
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DESCRIPTION OF EVENT
On January 7, 1994 the plant was operating at 100% power. The resid ?1 heat removal (RHR) system was in day 23 of a 30 day limiting condition for operation (LCO). Ongoing engineering reviews comparing Technical Specification limiting safety system setting nominal values, analytical limits, and surveillance test procedure (STP) limits' uncovered a deficiency in the testing of the average power range monitor (APRM) high flux scram trip setpoint.
Technical Specification 2.1. A.I. states that "The APRM scram trip setpoint
_f shall be... with a maximum setpoint of 120% rated power at 100% rated i
recirculation flow or greater...." STP 42C001-Q does test the APRM scram i
trip setpoint at 100% flow to assure that it is 120% rated power or less.
However, there has been no test at a recirculation flow greater than 100%
to assure that the scram setpoint does not exceed 120% rated power.
This condition was identified by plant engineers at 1230 hours0.0142 days <br />0.342 hours <br />0.00203 weeks <br />4.68015e-4 months <br /> on January 7, 1994 and was determined to be reoortable pursuant to-10CFR50.73(a)(2)(i)(B). At approximately 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> this condition was also determined to be reportable pursuant to 10CFR50.72(b)(2)(iii)(A) and 10CFR50.73(a)(2)(v)(A) as a condition that could have prevented the fulfillment of the safety function because the APRMs were considered to r
be inoperable. Subsequent tests showed that_this condition did not exist, as discussed below. In accordance with Technical Specification 3.1. A. the
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plant entered an LCO to be in at least Startup mode within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, effective at 1230 hours0.0142 days <br />0.342 hours <br />0.00203 weeks <br />4.68015e-4 months <br />.
t Also at'1230 hours0.0142 days <br />0.342 hours <br />0.00203 weeks <br />4.68015e-4 months <br /> on January 7, 1994 a revision to STP 420001-Q was initiated to add a test of the APRM scram trip setpoint at a simulated 125% rated recirculation flow. Following procedure approval, one revised test of all 6 APRMs' was begun. By 1810 hours0.0209 days <br />0.503 hours <br />0.00299 weeks <br />6.88705e-4 months <br /> 2 APRMs in each of the 2 trip systems had been tested with satisfactory as-found results and the LCO.
was exited. By 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br /> the remaining 2 of the total of 6 APRMs had also been satisfactorily tested.
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II. CAUSE OF EVENT
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The cause of this event (condition) was a lack of awareness of the requirement to test the flow biased APRM scram trip setpoint at a recirculation flow greater than 100%. This test confirms that the
" clamping" function on the scram trip.setpoint 'is set properly to limit the scram trip setpoint at 120% rated power or less when recirculation flow exceeds 100%. When this condition was identified it was agreed that i
the current STP was inadequate to test the " clamping" function.
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A factor that contributed to the lack of awareness was that two sections i
of the Technical Specifications, 1.1 Fuel Cladding Integrity and 3.1 Reactor Protection System Instrumentation, must be used together to understand all the test requirements.
III, ANALYSIS OF EVENT l
r The STP as-found test results on January 7, 1994 were all acceptable.
This verified that the " clamping" function on the flow biased scram trip setpoint had originally been and still is set properly. Therefore, the condition that existed before the revised STP was run had no effect on safe operation of the plant. The condition was only that the " clamping" I
function had not been tested. The APRM scram trip setpoint has been routinely tested at 100% rated recirculation flow. Recirculation flow i
and reactor power are monitored and controlled to prevent reactor power from exceeding the 100% licensed power level.
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IV. CORRECTIVE ACTIONS
During the time that the APRMs were considered to be inoperable, the reactor recirculation flow control system was locked in position to_
prevent a recirculation flow rate increase, and subsequent power increase, due to an electrical malfunction or manual initiation.
As discussed above, the STP for testing the flow biased APRM scram trip I
setpoint was revised to add a test of the " clamping" function by. testing i
at a simulated 125% rated recirculation flow. The revised STP was _
i sufficiently completed with satisfactory results to exit the LC0 within.
i the specified 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. The remainder of the STP was successfully completed within another hour. The STP revision is permanent and will be used for future testing.
A review of Technical Specification tables was performed to look for
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references, notes, or other requirements that may not have been included in surveillance tests. No more were found. The discovery of this-deficiency serves as a reminder, to those conducting the ongoing engineering reviews, of the need to carefully read the Technical i
Specification requirements and to carefully consider both the content and the intent of all references and footnotes.
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V. ADDITIONAL INFORMATION
A. Previous Similar Events A review of DAEC LERs since 1984 identified LERs 93-02, 91-11, 85-32 as reporting inadequate surveillance tests but none of these concern the APRM scram trip.
.i B. EIIS System and Component Codes 1
RHR--80 Reactor Recirculation--AD i
APRM--IG Reactor Power Control--JD This report is being submitted pursuant to 10CFR50.73(a)(2)(1)(B) and (a)(2)(v)(A).
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