05000346/LER-2016-008, Regarding Application of Technical Specification for the Safety Features Actuation System Instrumentation
| ML16245A294 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/30/2016 |
| From: | Boles B FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-16-239 LER 16-008-00 | |
| Download: ML16245A294 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3462016008R00 - NRC Website | |
text
FE NOC' RrstEnergy Nuclear Operating Company Brian D. Boles Vice President, Nuclear August30,2016 L-16-239 ATTN: Document Control Desk United States Nuclear Regulatory Commission Washington, D.C. 20555-0001
Subject:
Davis-Besse Nuclear Power Station, Unit 1 Docket Number 50-346, License Number NPF-3 Licensee Event Report 2016-008 5501 North State Route 2 Oak Harbor. Ohio 43449 10 CFR 50.73 419-321-7676 Fax: 419-321-7582 Enclosed is Licensee Event Report (LER) 2016-008-00, "Application of Technical Specification for the Safety Features Actuation System Instrumentation." This event is being reported pursuant to 10 CFR 50. 73(a)(2)(i)(B).
There are no regulatory commitments contained in this letter or its enclosure. The actions described represent intended or planned actions and are described for information only.
If there are any questions or if additional information is required, please contact Mr.
Patrick J. McCloskey, Manager-Site Regulatory Compliance, at (419) 321-7274.
Sincerely, Brian D. Boles vaw Enclosure: LER 2016-008-00 cc: NRC Region Ill Administrator NRC Resident Inspector NRR Project Manager Utility Radiological Safety Board
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 1013112018 (11-2015)
Estimated burden per response to comply with this mandatory collection requ*est: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported
.~l'lto"<.~o lessons learned are incorporated into the licensing process and fed back to industry. Send D
~
commenls regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-
~
s
=
LICENSEE EVENT REPORT (LER) 5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-
\\~4
- i mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory (See Page 2 for required number of Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503.
digits/characters for each block)
If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Davis-Besse Nuclear Power Station, Unit 1 05000 346 1 OF 5
- 4. TITLE:
Application of Technical Specification for the Safety Features Actuation System Instrumentation
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED I
SEQUENTIAL I REV FACIL\\1Y NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
MONTH DAY YEAR 05000 FACIL\\1Y NAME DOCKET NUMBER 06 30 2016 2016 -
008 00 08 30 2016 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
D 20.2201 (b)
D 20.2203(a)(3)(i)
D 50.73(a)(2)(ii)(A)
D S0.73(a)(2)(viii)(A) 1 D 20.2201 (d)
D 20.2203(a)(3)(ii)
D 50.73(a)(2)(ii)(B)
D 50.73(a)(2)(viii)(B)
D 20.2203(a)(1)
D 20.2203(a)(4)
D so.73(a)(2)(iii)
D 50.73(a)(2)(ix)(A)
D 20.2203(a)(2)(i)
D 50.36(c)(1)(i)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. POWER LEVEL D 20.2203(a)(2)(ii)
D 50.36(c)(1)(ii)(A)
D 50.73(a)(2)(v)(A)
D 73.71(a)(4)
D 20.2203(a)(2)(iii)
D so.36(c)(2)
D 50.73(a)(2)(v)(B)
D 73.71(a)(5)
D 20.2203(a)(2)(iv)
D so.46(a)(3)(ii)
D 50.73(a)(2)(v)(C)
D 73.77(a)(1) 100 D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(D)
D 73.77(a)(2)(i)
D 20.2203(a)(2)(vi)
[gj 50. 73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 73.77(a)(2)(ii) li*1; f.;). t\\Jci<. {,'t ;'j ~;, < ::
D 50.73(a)(2)(i)(C)
D OTHER Specify in Abstract below or in inches of water was chosen to provide the operator with an alarm and a permissive to allow timely operation of the BWST outlet and containment emergency sump valves to the long term recirculation position. This is to protect the pumps from cavitation for lack of proper net positive suction head and allow transfer of ECCS suction to the containment emergency sump from the BWST during the recirculation mode of operation before the inventory of the BWST is depleted.
Technical Specification(s):
Technical Specification (TS) Limiting Condition for Operation (LCO) 3.3.5 requires four channels of SFAS instrumentation for each parameter to be operable in each SFAS train. Failure of any instrument renders the affected channel( s) inoperable and reduces the reliability of the affected parameter and affected systems or components. With one or more parameters with one channel inoperable, Condition A requires one channel be placed in trip in one hour. With one channel placed in trip in an hour and Condition A not met, or one or more parameters with two or more channels rendered inoperable, Condition B requires the unit to be in Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
DESCRIPTION OF EVENT
The evaluation of this event is ongoing. The following description of the event is preliminary and subject to change, and will be updated via revision to this Licensee Event Report upon completion of the evaluation.
On June 30, 2016, at 0829, wit~ the DBNPS operating in Mode 1 at approximately 100 percent power, BWST SFAS Channel 1 Level Transmitter LT1525A was taken out of service for maintenance to replace the enclosure box and for calibration activities. SFAS Channel 1 was declared inoperable and TS LCO 3.3.5, Condition A was entered and the associated bistable for BWST Level was tripped. At 2342 hours0.0271 days <br />0.651 hours <br />0.00387 weeks <br />8.91131e-4 months <br /> with LT1525A still out of service, a failure of SFAS Channel 2 +15 Volt Power Supply occurred, rendering the SFAS Channel 2 inoperable, including SFAS Channel 2 BWST level instrument LT15258. BWST Level Transmitters for SFAS Channel 3 (LT1525C) and SFAS Channel 4 (LT1525D) remained operable. A separate entry into TS LCO 3.3.5 Condition A was made at 2342 hours0.0271 days <br />0.651 hours <br />0.00387 weeks <br />8.91131e-4 months <br />, but no entry into TS LCO 3.3.5 Condition B was made.
On July 1, 2016, at 0245 hours0.00284 days <br />0.0681 hours <br />4.050926e-4 weeks <br />9.32225e-5 months <br /> following a plant Duty Team discussion where the condition was re-assessed, the proper additional TS LCO 3.3.5, Condition B was entered as required for two channels of BWST level functions inoperable, which requires a plant shutdown to Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Following further discussions, between Operations and some Duty Team personnel, it was believed that SFAS Channel 1 could be considered operable with manual and compensatory actions due to the BWST Level - Low Low level being a transfer permissive that allows transfer to the Emergency Sump with less than nine feet of level in the BWST.
The compensatory actions were specific to SFAS Channel 1. Therefore, Operations exited TS LCO 3.3.5 Condition B at 0330 hours0.00382 days <br />0.0917 hours <br />5.456349e-4 weeks <br />1.25565e-4 months <br />.
06 After further management review, at 1325 hours0.0153 days <br />0.368 hours <br />0.00219 weeks <br />5.041625e-4 months <br /> it was determined the compensatory actions associated with BWST Level - Low Low level transmitter could not be supported and the previous operability determination for SFAS Channel 1 was invalid. Operations re-entered TS LCO 3.3.5, Conditions A and B.
==DESCRIPTION OF EVENT==YEAR 2016
- 3. LER NUMBER SEQUENTIAL NUMBER 008 Upon completion of maintenance and successful testing, SFAS Channel 1 BWST Level Transmitter (L T1525A) was declared operable at 1351 hours0.0156 days <br />0.375 hours <br />0.00223 weeks <br />5.140555e-4 months <br /> and TS LCO 3.3.5 Condition B was exited. Upoh replacement and testing of the +15 Volt power supply, SFAS Channel 2 was declared operable and TS LCO 3.3.5 Condition A was exited at 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br /> on July 1, 2016.
CAUSE OF'EVENT
)
The cause of this event is under evaluation and will be provided in a revision to this Licensee Event Report.
ANALYSIS OF EVENT
The BWST Level Transmitters monitor the BWST Level and initiate an SFAS Level 5 signal on BWST Level -
Low Low. This output signal provides a passive permissive interlock to allow operators the ability to shift ECCS suction from the BWST to the Emergency Sump by allowing operators to open the Decay Heat Pump Suction From Emergency Sump Valves and close tlie associated BWST Isolation Valves. The transfer of suction source from the BWST to the Emergency Sump is a manual transfer. The Probabilistic Risk Analysis (PRA) models failure of the SFAS Level 5 permissive signal, as well as failure of the valves 'to be repositioned
- (or failure of the human action to manually transfer the suction), which could result in the inability of the plant to shift ECCS suction from the BWST to the Emergency Sump.
The four-channel SFAS system is a 2-out-of-four circuit, such that any two level instruments which sense a BWST Level - Low Low will actuate the permissive interlock for both trains. With both L T1525A and L T1525B out of service, the SFAS BWST Level - Low Low passive permissive transfer was active (i.e., the valves could be repositioned to shift from the BWST to the Emergency Sump) as indicated by Annunciator 5-3-A., BWST LO-LO LVL XFER TO EMER SUMP. Since the permissive interlock was met, a failure of this SFAS Level 5 permissive signal is not possible.
Having the transfer permissive interlock active while the BWST was still full could permit operators to inadvertently transfer suction from the BWST to the Emergency Sump (violating procedure guidance) before there was adequate volume in the Emergency Sump. Additionally, having the transfer permissive annunciator 5-3-A lit significantly prior to reaching the BWST Level procedurally directing the transfer to the Emergency Sump could potentially increase the probability that the Operators would not take the action to transfer suction when the appropriate level was reached. However, by procedure and by 'training, Operators would monitor, log, and trend BWST level, so they would be aware when the proper time to transfer occurred, and there would be minimal increase in the failure to perform the required action.
Based on the above, the condition of having two BWST Level Transmitters out of service does not result in an increase in CDF, as calculated by thePRA model, and this condition would be considered to have a very low
safety significance
Reportability Discussion:
YEAR 2016
- 3. LER NUMBER SEQUENTIAL NUMBER 008 On June 30, 2016, at 2342 hours0.0271 days <br />0.651 hours <br />0.00387 weeks <br />8.91131e-4 months <br />, with the failure of SFAS Channel 2 Power supply, and SFAS Channel 1 BWST Level Transmitter previously declared inoperable for maintenance, TS 3.3.5, Condition B should have been entered due to the BWST parameter being inoperable for two channels of SFAS, requiring a 6-hour shutdown of the unit. However, as described above, while Condition B was entered on July 1, 2016 at 0245 hours0.00284 days <br />0.0681 hours <br />4.050926e-4 weeks <br />9.32225e-5 months <br />, it was inappropriately exited at 0330 hours0.00382 days <br />0.0917 hours <br />5.456349e-4 weeks <br />1.25565e-4 months <br />, and no shutdown initicited. Because the unit continued to operate after July 1, 2016, at 0542 hours0.00627 days <br />0.151 hours <br />8.96164e-4 weeks <br />2.06231e-4 months <br /> with two channels of SFAS inoperable, this represents continued operation or condition prohibited by the plant's Technical Specifications, which is reportable per 10 CFR 50.73(a)(2)(i)(B). On July 10, 2016, a retrospective notification was made to the NRC (Event Number 52079) for initiation of a plant shutdown as required by the TS that should have been made in accordance with 10 CFR 50.72(b)(2)(i). All safety systems performed as required in response to the event, and no loss of safety function occurred.
CORRECTIVE ACTIONS
Completed Actions:
Upon completion of maintenance and successful testing, SFAS Channel 1 BWST Level Transmitter
. (L T1525A) was declared operable.at 1351 hours0.0156 days <br />0.375 hours <br />0.00223 weeks <br />5.140555e-4 months <br /> on July 1, 2016. Upon replacement and testing of the +15 Volt power supply, SFAS Channel 2 was declared operable at 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br /> on July 1, 2016.
A standing order was issued on July 6, 2016 to reinforce the expectations for review of TS and Operability Determinations, and Duty Team and Licensed Operator standards and expectations.
Scheduled Actions:
Because the cause of this issue is still under evaluation, additional corrective actions will be provided in a revision to this Licensee Event Report.
PREVIOUS SIMILAR EVENTS
'/
DBNPS LER 2015-001 documents that the seismic BWST had been aligned in the past to the non-seismic Spent Fuel Pool system for purification. This rendered the BWST inoperable for periods of time longer than allowed per Technical Specification 3.5.4 while the plant was operating in Modes 1 through 4. However, this previous condition was not associated with the SFAS transfer permissive on BWST Level - Low Low, and the corrective actions taken for the previous event are not applicable to the current event. REV NO.
00