05000316/LER-2020-001, Failure of Source Range Nuclear Instrumentation Resulting in a Condition Prohibited by Technical Specifications

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Failure of Source Range Nuclear Instrumentation Resulting in a Condition Prohibited by Technical Specifications
ML20013D824
Person / Time
Site: Cook American Electric Power icon.png
Issue date: 01/09/2020
From: Lies Q
American Electric Power, Indiana Michigan Power Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
AEP-NRC-2020-02 LER 2020-001-00
Download: ML20013D824 (7)
v • d • e


LER-2020-001, Failure of Source Range Nuclear Instrumentation Resulting in a Condition Prohibited by Technical Specifications
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)
10 CFR 50.73(a)(2)(v), Loss of Safety Function
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
3162020001R00 - NRC Website
v • d • e

text

m INOIANA MICHIGAN POWER*

A unrt of American EJectnc Power January 9, 2020 Docket No.: 50-316 U. S. Nuclear Regulatory Commission A TIN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 Donald C. Cook Nuclear Plant Unit 2 LICENSEE EVENT REPORT 316/2020-001-00 Failure of Source Range Nuclear Instrumentation Resulting in a Condition Prohibited by Technical Specifications Indiana Michigan Power Cook Nuclear Plant One Cook Place Bndgman, Ml 49106 lnd1anaM1ch1ganPowar com AEP-NRC-2020-02 10 CFR 50.73 In accordance with 1 O CFR 50. 73, Licensee Event Report (LER) System, Indiana Michigan Power Company, the licensee for Donald *c. Cook Nuclear Plant Unit 2, is submitting as an enclosure to this letter the following report:

LER 316/2020-001-00: Failure of Source Range Nuclear Instrumentation Resulting in a Condition Prohibited by Technical Specifications There are no commitments contained in this submittal.

Should you have any questions, please contact Mr. Michael K. Scarpello, Regulatory Affairs Director, at (269) 466-2649.

Sincerely, l~At Site Vice President MPH/kmh

Enclosure:

Licensee Event Report 316/2020-001-00: Failure of Source'Range Nuclear Instrumentation Resulting in a Condition Prohibited by Technical Specifications

U. S. Nuclear Regulatory Commission Page 2 c:

R. J. Ancona - MPSC R. F. Kuntz - NRC Washington DC EGLE - RMD/RPS NRC Resident Inspector D. J. Roberts - NRC Region Ill A. J. Williamson - AEP Ft. Wayne AEP-NRC-2020-02

Enclosure to AEP-NRC-2020-02 Licensee Event Report 316/2020-001-00 Failure of Source Range Nuclear Instrumentation Resulting in a Condition Prohibited by Technical Specifications

NRCFORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)

Esllmated burden per re&p()flSe to comply w,th ths mandatofy collecbon request 80 hDln

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LICENSEE EVENT REPORT (LER)

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~..... 7 (See Page 2 fur reqi.-ed runber of d,glWcharaclers b-each block) to lnfocollecta Resource@!YC gov, 8lld to the Deek Officer, Office of lnfonnabon 8lld Regulatory Ma,rs, NEOB-10202, (3150-0104), Office of Management and Budget, Waahmgton, DC 20603 tf a (See NUREG-1022, R3 for Instruction and gl.11dance for completing this form mMns uaed to impose 811 information colectJon doeo not wplsy a C1fi8111ly valid 0"'3 control number, the NRC may not conduct or eponsor, and e person,a not required to re.pond to, the htto;l/www.((!;; oov/readll10ffll/doc-collecoons/nureos/staff/sr1022/r3/l imonnallon collecbon

3. PAGE Donald C. Cook Nuclear Plant Unit 2 05000316*

1 OF4

4. TITLE Failure of Source Range Nuclear Instrumentation Resulting in a Condition Prohibited by Technical Specifications
5. EVENT DATE
6. LER NUMBER
7. REPORT DATE
8. OTI-IER FACILmES INVOLVED YEAR rEQU~

REV FACILilY NAME DOCKET NUMBER MONTH DAY YEAR NO.

MONTH DAY YEAR NIA 05000 NU~ER FACIUTY NAME bOCKET NUMBER 11 13 2019 2020 001 00 01 09 2020 NIA

~5000

9. OPERATm MOOE
11. TIIS REPORT IS SUBMT1ED PlRSllANT TO TIE REQJREMENJ'S OF 10 CFR §: (Check all that apply) 3 D 202201(b)

D 20.2203(a)(3)(1)

D 50. 73(aX2X1l)(A)

D 50.73(a)(2)(vlflXA)

D 20.2201(d)

D 20.2203(a)(3)(n)

D 50.73(a)(2)01XB)

D 50.73(a)(2)(vtllXB)

D 20.2203(a)(1)

D 20.2203(aX4)

D 50.73(aX2)(11I)

D 50. 73(a)(2){1x)(A)

D 20.2203(a)(2)(1)

D 50.36(c)(1)(1XA)

D 50 73(aX2)(JVXA)

D 50.73(a)(2Xx) 1 o: POWER LEVEL D 202203(a)(2){11)

D 50.36(c)(1 )(ll)(A)

~ 50 73(a)(2)(v)(A)

D 73.71(a)(4)

D 202203(a)(2)011)

D 50 36(cX2)

D 50 73(a)(2)(v)(B)

D 73 11 (a)(5) 0 D 20.2203(a)(2)(1V)

D 50.48(a)(3){11)

D 50.73(a)(2)(v)(C)

D 73 77(a)(1)

D 20 2203(a)(2)(v)

D 50.73(a)(2)(t)(A)

D 50.73(aX2Xv)(D)

D 73.77(a)(2X1)

D 20.2203(aX2Xvt)

~ 50 73(aX2Xt)(B)

D 50.73(a)(2Xvtt)

D 73.77(a)(2Xn)

D 50 73(a)(2)(1)(C) 00THER Specify "' Abstract bew.¥ or n NRC Ferm 366A

12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT rflE NU"'3ER (lnoode IV9a Coda)

Michael K. Scarpello, Regulatory Affairs Director (269) 466-2649

13. CCM>l.ETE Of<E I.M FOO. EACH ca.1PONENT FAIUJRE DESCRIED IN 1HS REPORT

CAUSE

SYSTEM COMPONENT MANU-REPORTABLE

CAUSE

SYSTEM COMPONENT MANU-REPORTABLE FACTIJRER TO ICES FACTIJRER TO ICES X

IG DET WEST y

14. SUPPLEMENTAL REPORT EXPECTED
15. EXPECTED MONTH DAY YEAR 0 YES (If yes, complete 15. EXPECTED SUBMISSION DA TE}

[8) NO SUBMISSION DATE ABS l"RACT (l...mt lo 1400 speces, I e, ap(XOXJfTIBte/y 14 smgl&-spaced typewrTtten ioos)

On November 13, 2019, with Unit 2 in Mode 3, Operators were conducting rod drop measurement tests and the Channel 2 Source Range Neutron Flux Detector failed to indicate properly. A partial calibration of the detector channel was performed and declared operable. Following calibration, the detector again failed to respond as expected tq r~ctor rod withdrawals during sub-critical physics testing.

An evaluation concluded that the channel 2 source range detector was inoperable longer than allowed by Technical Specifications. Additionally, both channel 1 and channel 2 source range detectors were simultaneously inoperable for approximately 25 minutes on November 13, 2019. During the time when both source range detectors were inoperable, there were other nuclear instrumentation monitors available to alert Operators of any unexpected increase in neutron flux within the reactor core. The cause of the failure was determined to be a degraded connection on a newly installed trlaxlal cable connector. The cable and the degraded connectors were replaced wlth an installed spare.

Therefore, this event is reportable as an Operation or Condition Prohibited by Technical Specifications in accordance with 1 OCFRSO. 73(a)(2){1)(B) and as an Event or Condition that Could Have Prevented Fulfillment of a Safety Function In accordance with 1 OCFRSO. 73{a)(2)(v)(A).

NRC FORM 366 (04-2018)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104,

EXPIRES: 03/31/2020

EVENT DESCRIPTION

3.LER~

SEQUENTIAL NUMBER

- 001 REV NO
- 00 Technical Specification (TS) Limiting Condition for Operation (LCO) 3.3.1, Reactor Trip System (RTS)

Instrumentation, requires two Source Range Neutron Flux Trip channels to be operable in Modes 3, 4, and 5 when the Rod Control System [AA] is capable of rod withdrawal, or one or more rods are not fully inserted. With one Source Range Neutron Flux Trip Channel inoperable in Modes 3, 4, or 5, the required action is to restore the channel to operable status within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. If the required action completion time is not met, then the requirement is to immediately take actions to fully insert all rods and to place the Rod Control System in a condition incapable of rod withdrawal within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Additionally, if two Source Range Neutron Flux Trip Channels are inoperable in Modes 3, 4, or 5, the required action is to immediately open the Reactor Trip Breakers (RTBs).

TS LCO 3.3.8, Boron Dilution Monitoring Instrumentation (BDMI), requires two Source Range Neutron Flux Monitoring channels to be operable in Modes 3, 4 and 5. When one Source Range Neutron Flux Monitoring Channel is inoperable in Modes 3, 4, or 5, the Required Action is to restore the Channel to operable status within 7 days.

On November 13, 2019, at 2102 hours0.0243 days <br />0.584 hours <br />0.00348 weeks <br />7.99811e-4 months <br />, with Donald C. Cook Nuclear Plant Unit 2 in Mode 3, during performance of the procedure for Multiple Rod Drop Measurements, 2-NRl-32 (Nuclear Instrumentation Channel 2 Source Range Neutron Flux Detector) [IG] [DET] failed to indicate properly. A partial calibration of the detector channel was performed and 2-NRl-32 was declared operable at 1428 hours0.0165 days <br />0.397 hours <br />0.00236 weeks <br />5.43354e-4 months <br /> on November 14, 2019. Subsequently, during sub-critical physics testing at 2002 hours0.0232 days <br />0.556 hours <br />0.00331 weeks <br />7.61761e-4 months <br /> on November 14, 2019, 2-NRl-32 again failed to respond as expected to Shutdown and Control Bank withdrawals.

As a result of the second failure, a Past Operability Determination Evaluation (PODE) was performed and concluded that 2-NRl-32 was inoperable per TS 3.3.1 from 0050 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br /> on November 13, 2019, when the Unit 2 RTBs were closed, until the RTBs were re-opened at 1556 hours0.018 days <br />0.432 hours <br />0.00257 weeks <br />5.92058e-4 months <br /> on November 15, 2019, for a total of 63 hours7.291667e-4 days <br />0.0175 hours <br />1.041667e-4 weeks <br />2.39715e-5 months <br /> and 6 minutes. The period over which 2-NRl-32 was inoperable exceeded the time allowed by TS 3.3.1. Additionally, both Source Range Channels were inoperable from 0307 hours0.00355 days <br />0.0853 hours <br />5.076058e-4 weeks <br />1.168135e-4 months <br /> to 0332 hours0.00384 days <br />0.0922 hours <br />5.489418e-4 weeks <br />1.26326e-4 months <br /> on November 13, 2019 when 2-NRl-31 (Nuclear Instrumentation Channel 1 Source Range Neutron Flux Detector) was removed from service and rendered inoperable during high flux shutdown adjustments and 2-NRl-32 was also inoperable.

The PODE also determined that 2-NRl-32 was inoperable, per TS LCO 3.3.8, from the time Unit 2 entered Mode 5 at 0052 hours6.018519e-4 days <br />0.0144 hours <br />8.597884e-5 weeks <br />1.9786e-5 months <br /> on November 5, 2019, until 1017 hours0.0118 days <br />0.283 hours <br />0.00168 weeks <br />3.869685e-4 months <br /> on November 18, 2019, for a period of 13 days, 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> and 25 minutes. The period over which 2-NRl-32 was inoperable exceeded the time allowed by TS 3.3.8.

Therefore, this event is reportable as an Operation or Condition Prohibited by Technical Specifications in accordance with 10CFR50.73(a)(2)(i)(B) and as an Operation or Condition that Could Have Prevented Fulfillment of a Safety Function in accordance with 10CFR50.73(a)(2)(v)(A). Page 2 of 4

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)

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CONTINUATION SHEET Reguaixy Conm98ton, Wastnngton, DC 20555-0001, or by 1H!l811 to lrtocoGect!I Resource@nrc gOY, and lo the Desk Officer, Office of lnfoonalion sat Regulalo,-y 1------------------------1 Affairs, NEOB-10202, (3150-0104), Office of Mooagemert Bild Budget, Was/1Jr¢ln, DC 20503 If a (See NU RE G-1 022, R.3 for Instruction and guidance for com plebng this form m81111S l.l88d kl impose an Irronnaoon coled!on does not d1aplay a ct.rnn!ly vmd 0MB control httpJ/yNyW.nrc.goy/readjng;m/doc-coilecbons/nureqs/staff/sr1022/r3{)

nUIWBr, the NRC may not conduct or sponsor, i.id a person m not reqUJred to respond to, the 1rmmallon collection.

1. FACILITYNAME
2. DOCKET NUMBER YEAR Donald C. Cook Nuclear Plant Unit 2 05000316 2020 COMPONENTS 2-NRl-32: Nuclear Instrumentation Channel 2 Source Range Neutron Flux Detector.

CAUSE OF THE EVENT

3. LERNLNBER SEQUENTIAL NUl.l3ER
  • 001 REV NO
  • 00 The cause of the failure was determined to be a degraded connection on a newly installed triaxial cable connector.

CORRECTIVE ACTIONS

The cable and the degraded connectors were replaced with an installed spare.

ASSESSMENT OF SAFETY CONSEQUENCES

NUCLEAR SAFETY For the 13 days, 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> and 25 minutes, when 2-NRl-32 was inoperable for indication and audible count rate, per TS 3.3.8, 2-NRl-31 was operable, except for the 25 minutes that both Source Range Channels were inoperable, and would have been the primary method of detection for an unintended increase in reactivity. Additionally, Operators were monitoring both the Thermo Gamma-Metrics neutron flux monitors and the Volume Control Tank (VCT) level. A sudden increase in neutron flux observed in the Gamma-Metrics monitor or an unexpected change to VCT level would prompt Operators to investigate and subsequently discover the boron dilution event.

For the 63 hours7.291667e-4 days <br />0.0175 hours <br />1.041667e-4 weeks <br />2.39715e-5 months <br /> and 6 minutes, when 2-NRl-32 trip function was inoperable per TS 3.3.1, 2-NRl-31, except for the 25 minutes that both Source Range Channels trip functions were inoperable, as well as the intermediate range and power range detectors were capable of detecting neutron flux and would have provided a reactor trip signal.

For the 25 minutes that both Source Range Channels were inoperable for indication and audible count rate, per TS 3.3.8, the Thermo Gamma-Metrics monitor and VCT level indications were available to the Operators to monitor and respond to a boron dilution event. For the 25 minutes that both Source Range Channels trip functions were inoperable, the intermediate range and power range detectors were capable of detecting neutron flux and would have provided a reactor trip signal.

Therefore, there was no actual or potential nuclear safety hazard resulting from the inoperable Source Range Neutron Flux Detector(s). Page 3 of 4

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 31!50-01CM EXPIRES: 03/31/2020 (04-2018)

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runber, the N RC may not conduct or epoosor, 011d a pereon i! not reqwred lo respond to, the 1rrormallon collection

1. F N:;IUTY N/WE
2. DOCKET Nl.NBER YEAR Donald C. Cook Nuclear Plant Unit 2 05000316 2020 INDUSTRIAL SAFETY SEQUENTIAL NUMBER
- 001 REV NO
- 00 There was no actual or potential industrial safety hazard resulting from the inoperable Source Range Neutron Flux Detector(s).

RADIOLOGICAL SAFETY There was no actual or potential radiological safety hazard resulting from the inoperable Source Range Neutron Flux Detector(s).

PROBABILISTIC RISK ASSESSMENT The Probabilistic Risk Assessment (PRA) model does not credit the source range detectors as indicators.

to take plant actions, and thus a qualitative approach was used to assess risk of the event. During the time that one or both source range detectors were inoperable, The Intermediate Range detectors, the Power Range detectors, and the Thermo Gamma-Metrics neutron flux monitors were all available as visual indicators in the control room to monitor core flux in the event of a Boron Dilution. The trip functions for Intermediate and Power Range were all available to protect against an uncontrolled rod withdrawal.

Therefore the overall risk is estimated to be of very low safety significance.

PREVIOUS SIMILAR EVENTS

A review of Licensee Event Reports for the past three years found no similar events.

NRG FORM 386A (04-2018)

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