05000334/LER-2019-002, Manual Reactor Trip at 15% Power Due to Lifting of the 1A Main Steam Safety Valve
| ML20003D854 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 12/30/2019 |
| From: | Penfield R FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-19-292 LER 2019-002-00 | |
| Download: ML20003D854 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2) 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)(1) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 3342019002R00 - NRC Website | |
text
FENOC' RrstEnergy Nuclear Operating Company Rod L. Penfield Site Vice President December 30, 2019 L-19-292 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 LER 2019-002-00 10 CFR 50.73 Beaver Valley Power Station P.O. Box 4 Shippingport, PA 15077 724-682-5234 Fax: 724-643-8069 Enclosed is Licensee Event Report (LER) 2019-002-00, "Manual Reactor Trip at 15%
Power Due to Lifting of the 1A Main Steam Safety Valve." This event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A).
There are no regulatory commitments contained in this submittal. Any actions discussed in this document that represent intended or planned actions are described for the NRC's information, and are not regulatory commitments.
If there are any questions or if additional information is required, please contact Mr. Steve Sawtschenko, Manager, Regulatory Compliance and Emergency Response, at 724-682-4284.
Sincerely, 1t}e, ~
Rod L. Penfield Site Vice President Enclosure - Beaver Valley Power Station, Unit 1 LER 2019-002-00 cc:
Mr. D. C. Lew, NRC Region I Administrator Mr. J. A Krafty, NRC Senior Resident Inspector Ms. J.C. Tobin, NRC Project Manager INPO Records Center (via INPO Industry Reporting and Information System}
Mr. L. Winker (BRP/DEP)
Enclosure L-19-292 Beaver Valley Power Station, Unit 1 LER 2019-002-00
NRCFORM366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150*0104 EXPIRES: 03/31/2020 (04-2018)
, the NRG may not conduct or sponsor, and a person Is not required to JI,****"'
respond to, the lnformatton coUecfion.
3.Page Beaver Valley Power Station Unit 1 05000 334 1
OF 3
- 4. Title Manual Reactor Trip at 15% Power Due to Lifting of the 1 A Main Steam Safety Valve
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved Month Day Year Year I Sequential I Rev Month Day Year t-acunyName Docket Number Number No.
N/A 05000 11 04 2019 2019 002 00 Faclllty Name Docket Number 12 30 2019 N/A 05000
- 9. Operating Mode
- 11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply)
D 20.2201(b)
=i 20.2203(a)(3)(1)
D 50.73(a)(2)(Jl)(A)
D 50. 73(a)(2)(vlll)(A) 1 D 20.2201(d)
- J 20.2203(a)(3)(1i)
D 50. 73(a)(2)(ii)(B)
D 50. 73(a)(2)(viii)(B)
D 20.2203(a)(1)
=i 20.2203(a)(4)
D 50.73(a)(2)(ili)
D 50. 73(a)(2)(ix)(A)
- J 20.2203(a)(2)(i)
- J 50.36(c)(1 )(l)(A)
Q
- 50. 73(a)(2)(iv)(A)
D 50. 73(a)(2)(x)
- 10. Power Level
- J. 20.2203(a)(2)(ii)
=i 50.36(c)(1 )(ii)(A)
D 50.73(a)(2)(v)(A)
=i 73.71(a)(4)
- J 20.2203(a)(2)(iii)
=i 50.36(c)(2)
D 50.73(a)(2)(v)(B)
D 73.71(a)(5)
- J 20.2203(a)(2)(1v)
=i 50.46(a)(3)(ii)
D 50.73(a)(2)(v)(C)
D 73. 77(a)(1) 15
=i 20.2203(a)(2)(v)
=i 50.73(a)(2)(1)(A)
D 50.73(a)(2)(v)(D)
D 73. 77(a)(2)(i)
=i 20.2203(a)(2)(vi)
=i 50. 73(a)(2)(J)(B)
D 50.73(a)(2)(vii)
D 73. 77(a)(2)(ii)
- \\(}\\
- ',.\\?,.,' (/' *f ::~)i =i 50. 73(a)(2)(1)(C)
D Other (Specify in Abstract below or in Energy Industry Identification System (EIIS) Codes identified in the text as [XX].
CONDITIONS PRIOR TO OCCURRENCE:
Beaver Valley Power Station Unit 1 (BV-1) was in Mode 1 at approximately 15% reactor power, starting up from a refueling outage.
There were no Structures, Systems, or Components that were inoperable at the start of the event that contributed to the event.
DESCRIPTION OF EVENT
On November 4, 2019, at 0535 Eastern Standard Time, BV-1 reactor was manually tripped at approximately 15% reactor power due to secondary system perturbations that caused the 1A Main Steam Safety Valve (MSSV) [SB] to lift.
The unit was starting up from a refueling outage and shortly after reaching the point of adding heat at 0403 hours0.00466 days <br />0.112 hours <br />6.66336e-4 weeks <br />1.533415e-4 months <br />, the three Main Feedwater Regulation Valve Bypass Valves (MFRV Bypass Valves) [SJ] were noted to have oscillations. Upon stabilizing the unit at 15% power, oscillations were noted on the secondary side of the plant (Steam Generator levels [JB],
steam flows [SB], MFRV Bypass Valve control station demand signal and Condenser Steam Dump Valve (CSDV) [JI] control station demand signal). At 051 O hours, the secondary perturbations degraded with oscillations in Steam Generator levels noted to be fluctuating approximately 2-3%. Field operators reported that all three MFRV Bypass Valves were cycling excessively and controlling over the entire valve stroke range (full closed/full open).
A Reactor Operator (RO), the Reactivity Senior Reactor Operator, and the Unit Supervisor discussed and agreed to place the CSDV Auto/Manual station to Manual in accordance with the short term configuration control process in an attemptto settle out the MFRV Bypass Valve oscillations.
The CSDV controller demand was increased to reduce Reactor Coolant System (RCS) [AB] average temperature.
Pressurizer pressure decreased as a result and went below the limit required by Technical Specification 3.4.1, Reactor Coolant System Pressure, Temperature, and Flow Departure from Nucleate Boiling (DNB) Limits. The CSDV controller demand was then reduced to maintain RCS average temperature within the control band. At 0516 hours0.00597 days <br />0.143 hours <br />8.531746e-4 weeks <br />1.96338e-4 months <br />, operators observed that the 1 B and 1 C Steam Generator Atmospheric Dump Valves (ADV) [SB] had both opened due to high steam generator pressures. The 1A ADV was not opened, and reports were received that the 1A MSSV was open. The 1A MSSV remained open below the expected blowdown pressure referenced in operating manual procedures.
The RO reported that reactor power was continuing to rise (increase of approximately 0.5% power) due to the increasing steam flow. Due to the 1A MSSV remaining open and the 1s1 bank of CSDVs open (with steam generator pressures dropping) and reactor power increasing, the control room staff made a conservative decision to manually trip the reactor at 0535 hours0.00619 days <br />0.149 hours <br />8.845899e-4 weeks <br />2.035675e-4 months <br />.
The 1A MSSV reseated around the time of the reactor trip, and the control room staff stabilized the plant in accordance with post-trip procedures. The trip response was not complex as an systems responded normally post trip. All control rods [AA]
fully inserted to shutdown the reactor, and the plant was stabilized in Mode 3 with normal Main Feedwater System [SJ] in service.
NRC FORM 366 (04-2018)
Page2 of3
CAUSE OF EVENT
The reason for the MSSV opening prior to the 1A ADV opening was due to the as-left setpoint of the 1A ADV pressure switch during its calibration in the Spring 2018 refueling outage.
The 1A ADV has a trip open feature that is expected to occur at 1060 psig. This feature is activated by a pressure switch which is calibrated to a tolerance of +/- 10 psig. During the previous refueling outage, the pressure switch as-left setting was 1068 psig, near the setpoint upper tolerance range of 1050 to 1070 psig. Additionally, following the reactor trip, the as-found trip setpoint of this pressure switch was found at 107 4 psig, resulting from a drift that was high out of tolerance and above 1 A MSSV lift setpoint of 1068 psig.
Prior to the trip, steamline pressure reached 1068.3 psig and satisfied the lift setpoint of 1075 psig (1085.75 psig-1042.75 psig) for the MSSV. The MSSV reseated when pressure was reduced.
ANALYSIS OF EVENT
The plant risk associated with the unexpected opening of 1A MSSV and manual reactor trip that occurred on November 04, 2019 is considered to be very low. This is based on the conditional core damage probability and conditional large early release probability for this event.
This event was reported per Event Notification 54369 as an actuation of the Reactor Protection System per 10 CFR
- 50. 72(b)(2)(iv)(B). This written report is submitted pursuant to 1 O CFR 50. 73(a)(2)(iv)(A) as a condition that resulted in the manual actuation of the Reactor Protection System.
CORRECTIVE ACTIONS
- 1. The pressure switch input to the 1 A ADV was adjusted to within the tolerance band. (Completed on November 05, 2019).
- 2. An Engineering Evaluation established new setpoint and reset values for the three ADV pressure switches. Work orders are scheduled per the Work Management Process.
Completion of item 2 listed above is being tracked in the Corrective Action Program.
PREVIOUS SIMILAR EVENTS
Condition Report 2009-59531 documents that on May 21, 2009, the MFRV Bypass Valves began to cycle 25-40% while in auto_r,:iatic control at approximately 15% power. An operator took manual control of the CSDV controller in an attempt to stabilize Steam Generator pressure. As this evolution was in progress, the 1A MSSV lifted. Corrective Actions concluded there was no design issue with the safety code lifting, and the MSSV setpoint and accumulation can overlap with the ADV range.
Condition Report 2019-09324 NRC FORM 366 (04-2018)