05000331/LER-1997-001, :on 970115,failure to Comply with TS for Main Steam Line Radiation Monitors Occurred.Caused by Less than Adequate Implementation of post-outage NMCA Test.Mslrm Were Set in Accordance with TS
| ML20138L729 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 02/14/1997 |
| From: | Middlesworth G, Murrell R IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT |
| To: | Beach A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| LER-97-001, LER-97-1, NG-97-0320, NG-97-320, NUDOCS 9702250020 | |
| Download: ML20138L729 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2) |
| 3311997001R00 - NRC Website | |
text
Cuare Amcid Energy Cemer c
3:77 DAEC Road P3:0. IA $23:4 Tenephone 319 8517611 Fax 319 85I 7611 UTILITIES February 14,1997 NG-97-0320 Mr. A. Bill Beach Regional Administrator Region III U. S. Nuclear Regulatory Commission 801 Warrenville Road Lisle,IL 60532
Subject:
Duane Arnold Energy Center Docket No: 50-331 Op. License No: DPR-49 Licensee Event Report #97-01 File:
A-118a Gentlemen:
Please find attached a copy of the subject Licensee Event Report in accordance with 10CFR50.73. There are no new commitments made in this letter.
Sincerely, af a+1 AY
<td Gary Van Middlesworth Plant Manager - Nuclear cc:
Director of Nuclear Reactor Regulation -
Document Control Desk U. S. Nuclear Regulatory Commission Mail Station Pl-37 Washington, D. C. 20555-0001 NRC Resident Inspector - DAEC
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FACILfTY NAME (1)
DOCKET hUMBER G)
PAGE (3)
Duane Arnold Energy Center 05000-331 1OF3 i
TITLE 64)
Failure to Comply with Technical Specification for Main Steam Line Radiation Monitors i
EVENT DATE (5)~
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED (8)
MONTH DAY YEAR YEAR 5tuutNTIAL HLVlMUN MONTH UAY YEAR FAWTY NAME Ro utTNUMets NUMBER NUMBER 05000-331 3
1 15 97 97 -
01
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14 97 FAWD NAME NE r Nym 1
05000-331 OPERATING THIS REPORT IS SUBMIT Iw PURUUANT TO THE R EQUIREM"ENTS OF 10 CFR 5: (Check one or more) (11)
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j MODE (9) 1 20.2201(b) 20 ZZO3(aH2Hvs X
50.73(a)(2)D) 50.73(aH2Hvin)
POWER 20.2203(aH1) 20.2203 a)(3)(i) 50.73(a)(2)Dil 50.73(aH2Hx)
LEVEL (10) 100 20.2203(aH2Hi) 20.220maH3)0s) 50.73(a)(2)(in) 73.71 1
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i %ENSEE CONTACT FOR THIS LER (121 NAME TELEPHONE NUMBER (inciude Asad Godes Robert Murrell, Licensing Speckliist 319-851-7900 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESGRIBED IN THIS REPORT (13)
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During Refueling Outage (RFO) 14, the Duane Arnold Eriergy Center (DAEC) performed Noble Metal Chemical Addition (NMCA). This is a first of a kind process to allow corrosion protection of vessel internals with decreased Hydrogen Water Chemistry (HWC) injection rates and lower radiation dose rates at the facility. On January 15,1997, following the November 16,1996 plant startup from RFO 14, it was determined that the DAEC failed to meet the requirement of Technical Specifications (TS) Table 3.2-A, in that the Main Steam Line Radiation Monitors (MSLRMs) were not set to trip at 5: 3 x Normal Rated Power Background. The MSLRMs were set to trip at a setpoint non-conservative with respect to the TS requirement. Implementation of the post-outage NMCA test failed to establish timely interim re-establishment of" Normal" radiation levels and the corresponding setpoint change.
NRC FDRM 366 I4 95)
.U.S. NUCLEAR REGULATORY CoMMISSlo (499 UCENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET LER NUMBER (6)
PAGE (3)
%g M
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N Duans Arnold Energy Center 05000-331 97 01 00 TEXT (11 more space os required, use additional copies of NRC Form 366A) (17)
1. DESCRIPTION OF EVENT
During Refueling Outage (RFO) 14, the Duane Arnold Energy Center (DAEC) performed Noble Metal Chemical Addition (NMCA). This is a first of a kind process which will provide corrosion protection of vessel internals with decreased Hydrogen Water Chemistry (HWC) injection rates. This will result in lower radiation dose rates at the facility.
On January 15,1997, it was determined that the DAEC failed to meet the regmreu.at of Technical Specifications (TS) Table 3.2-A, in that the Main Steam Line Radiation Monitors (MSLRMs) were not set to trip at 5 3 x Normal Rated Power Background. The MSLRMs were set to trip at a setpoint of 1800 mr/hr from startup from RFO 14 (November 16,1996) until December 18,1996. This setpoint corresponded to a Hydrogen Water Chemistry (HWC) injection rate of 15 scfm (previous cycle injection rate). HWC injection rates after startup were approximately 6 scfm from November 20 until December 18,1996, except for periods of testing. Radiation readings in the vicinity of the MSLs were approximately 150 mr/hr with HWC set at an injection rate of approximately 6 scfm, hence the trip setpoint should have been approximately 450 mr/hr (3x). TS Table 3.2-A states: "If the minimum operable channels per trip system" cannot be met, then follow action statement 21. Action statement 21 requires the plant to be in at least STARTUP with the associated isolation valves closed within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> or be in at least HOT SHUTDOWN within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the next 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Although the MSLRM setpoint of 1800 mr/hr was conservative with respect to the design basis, it was non-conservative with respect to TS. DAEC failed to meet this TS requirement between November 24,1996 (when rated power was reached) and December 18, 1996.
II. CAUSE OF EVENT
The root cause of this event is less than adequat. implementation of the post-outage NMCA test. The test failed to establish provisions for timely interim re-establishment of" Normal" radiation levels and the corresponding setpoint change prior to placing HWC in service for startup from RFO 14. The DAEC staff accepted a definition of" Normal" that had been established based on historical operating parameters. Prior to startup from RFO 14, it was understood that there would be a need to adjust the MSLRM set points to correspond with a different HWC injection rate. The injection rate would be dependent upon a General Electric (GE) evaluation of the results of the post-Noble Metal Chemical Addition test. This test required HWC to be varied to determine the effectiveness of Noble Metal Chemical Addition. It was anticipated that the new value of" Normal" would not be established (by GE) until January,1997. While the planning recognized that changes were likely to occur in HWC injection rates, the DAEC statT focused on the design basis safety function of the MSLRMs and did not fully recognize the interim operation at lower HWC rates as establishing a new " Normal" value in accordance with TS.
eU.S. NUCLEAR REGULATORY COMMISSIO W 95)
UCENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET LER NUMBER (6)
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M Duane Arnold Energy Center 05000-331 97 -
01 00 T EXT Ut more space is required, use adoitsonal copies of NRC Form 366A) (17)
III. ANALYSIS OF EVENT
The safety objective of the MSLRM system is to monitor for gross release of fission products from the fuel (Control Rod Drop Accident) and, upon indication of such release, to initiate appropriate action to limit fuel damage and contain the released fission products. A trip setting of 3 times normal full-power background is established to close the MSL drain valves, recirculation loop sample valves, and trip the mechanical vacuum pump. Radiation Engineering Calculation 94-014A (performed in 1994) developed an upper bounding value for the MSLRM high radiation trip setpoint of 6000 mr/hr using the source term radiation values for the Control Rod Drop Accident specified in Chapter 15 of the Updated Final Safety Analysis Report. The trip setnaint during the period of TS non-compliance for the MSLRM trip setpoint was 1800 mr/hr. This setpoint was substantially under the bounding value. The small increase in delay time to reach the setpoint was not significant and would not have caused an increased activity release to challenge dose rates governed by 10 CFR 100. Smaller fuel failures, outside the bases of the MSLRMs, would be detected by the Offgas Pretreatment Radiation Monitors and/or the Offgas Stack Radiation Monitors. During the period in question, the main steam line drain valves were closed and the mechanical vacuum pump was not in service.
4 Recirculation loop sample lines were open but would have closed when MSLRM levels reached approximately 1800 mr/hr.
IV. CORRECTIVE ACTIONS
On December 18,1996 the HWC injection rate was raised to 15 scfm to ensure that the MSLRM were set in accordance with TS.
On December 21,1996, Engineering Maintenance Action A27877 lowered the MSLRM set points to match the GE recommended HWC injection rate and HWC injection rate was reduced. Surveillance Test Procedures were revised to reflect the revised setpoints for future calibrations.
DAEC's conversion to improved Standard Technical Specifications is currently on the docket. The proposed MSLRM set point will be a value consistent with the design basis. This corrective action will eliminate the ambiguity surrounding the word " Normal."
V. ADDITIONALINFORMATION:
i None