05000219/LER-2014-006-01, Regarding Reactor Scram Due to Decreasing Reactor Water Level

From kanterella
Jump to navigation Jump to search
Regarding Reactor Scram Due to Decreasing Reactor Water Level
ML15251A205
Person / Time
Site: Oyster Creek
Issue date: 08/24/2015
From: Dostal J
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
RA-15-072 LER 14-006-01
Download: ML15251A205 (4)
v • d • e


LER-2014-006, Regarding Reactor Scram Due to Decreasing Reactor Water Level
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)
10 CFR 50.73(a)(2)(v)(6)
10 CFR 50.73(a)(2)(iv)(A), System Actuation
2192014006R01 - NRC Website
v • d • e

text

RA-1 5-072 10 CFR 50.73 August 24, 2015" U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 - 0001 Oyster Creek Nuclear Generating Station Renewed Facility Operating License No. DPR-16 NRC Docke N.5-29

Subject:

Licensee Event Report (LER) 2014-006-01, Reactor SCRAM due to Decreasing Reactor Water Level Enclosed is Revision 01 to LER 2014-008, Reactor Scram due to Decreasing Reactor Water Level, which occurred on October 12, 2014. This revision includes additional information from the Root Cause Report and subsequent Corrective Actions from the event. This event did not affect the health and safety of the public or plant personnel. This event did not result in a safety system functional failure. There-are no regulatory commitments made in this LER submittal.

Should you have any questions Concerning this ietter, please contact Michael MoKenina, Regulatory Assurance Manager, at (609) 971-4389....-

.+..

Respectfully, Jeffrey'P ot Plant Manay Oyster Creek Nuclear Generating Station Enclosure: NRC Form 366, LER 2014-006-01 cc:

Administrator, NRC Region 1 NRC Senior Resident Inspector - Oyster Creek Nuclear Generating Station NRC Project Manager - Oyster Creek Nuclear Generating Station

I0-214

='

.Estimated burden per response to comply with t*s redao collection requesl: 80 hOuLs,

  • t, ;

Rapofled leeo lea~n erd in ~orpoeatod into the lIetnain proesse aned fed beck to Ind'usby.

Send conanento regardtng burdene~alin to the FOLAK Privacy and Informtion l

C~oiteolons

- LICENSEE EVENT REPORT (LER)

Braich rT8 F53), U.S...

Nu*e Re

  • LyCo*n Was1ge, DC 205.001, or by ihz ssb to In ococt&R

@nrvogov, end to to De O flz cu 0

1f-1,O'cc of Inform'atn mrid (See Page 2 for' required number of RgiR loy

  • faa NEoB-02,Z (3180-o104), o1k of aaeTet*

andBude, Washngo. DC digits/characters for each block) zo0*

tfe NEC u* to r*o on,= edoa prso Is no reqart reson t Ir mona*o colectio.

Reactor SCRAM due to Decreasing Reactor Water Level...

9. OPERATING MODE It.._THIS REPORT. IS SU6MEDIE PURSUANT TO T"HE REQUIREMENTS.OP= 10 CF 5 (Check al that aply)

O...C 20.22O1(b) 0i 20.2203(a)(3)(i) 0

[

50.73(a)(2)(t(C) -

E] 5O.73(a)(2)-(viI)

[] 20.221(d) 0] 20.2203(a)(3)(,)

0] 50.73(a)(2)(iI)(A)

El 50.73(a)(2)(vI,)(A)

N 0 20o.2o3(e)(1)

[20.2203(a)(4) 0] 5o.3()(2)(,)(B) 0] 50.73(a)(2)(viI)(B) 020(X)s 0.* 50 IJ.38c()OA 507(a()I I* I III0 50171 (I)(2)(Ix)

El. 20.220*(a)(2)(iv)..

El, 50.48(s)(3)(tH).

0F 50.73(a)(2)(v)(6).

0 73.71(a)(5),.

Michael McKenna, Regulatory Assurance Manager.

1(809) 971-4389-

14. SUPPLEMENTAL. REPORT EXPECTED
15. E.XPCTD...

1*m' I1,YI YR YES (I f yes. copete"15 EXPECrTED SUBMISI*ON DATE)

Eg wo S~lUOtS 0--- 13 15

$BSTRACT (Lirmit to 1400 space,

  • oI.o., appronimaeyf ot l8an~e-spacB4 type wuiten lines).."

On October 12, 2014, an automati SCRAM occurred during the reactor startup evolution following the 1R25 refueling outage. The SCRAM occurred when a station electrfcian, in conjuncton with a General Electric technician and a site engineer,, secured power to the Main Generator Automatic Voltage Regulator (AVR).controllers :while the Main Turbine warming evolution was in progress. The individuals were not authorized to perform this action nor did they have procedures ln'the field to operate the equipment. Their actions resulted in an automatic reactor SCRAM on low water*

level.

ENS 50524 was submitted on October 12, 2014, and updated on October 17, 2014.r This issue is reportable under 10 CFR 50.73(a)(2)(iv)(A), because it involved an event or condition that resulted in manual or automatic actuation of any of the systems listed in paragraph (a)(2)(iv)(B). -..-

The Root Cause Analysis was completed on January 30, 2015. The cause of this event was determined to be that Station Leadership has inconsistently reinforced Human Performance Error Reduction Tool Use and Procedure Use *

  • and Adherence. This resulted in the breakdown of multiple fundamental practices and standards that led to the event.

NRC FORM 3866(01-2014)

IRC FORM SG US. N*UCLEAR REGULATORY COMMISSION L0PROVED -BY 0MB: NO.1600*-150*4 E.XPIRES: 01131017 istanot 1hi gInocdeie*.otac@mc.

, an to Vh, Desk Off~e. Offie of onat S1FALTYNAME

.... DOCKET

6. LEA NUMBR..

C. PAGE 1.FCIT I

IUENTIAL REV Oyster Creek, Unit 1 05000219 2

OF 3

Ij 2014 006 01

NARRATIVE

Description of Event

On October 12, 2014, during a planned reactor power ascension with reactor power at approximately 1% of rated thermal power, reactor water level began lowering. An automatic SCRAM occurred at 0261 EDT, moments before

In this condition, the Turbine Bypass Valves (TBeV) are held open by the Bypass Valve Opening Jack (BVOJ) with the internal bypass of the #2 TBV open, admitting steam to the Low Pressure (I.P) turbine. in this state, when the turbine is tripped, Turbine Emergency Trip Oil pressure is dumped, which closes the TSVs and Turbine Control Valves (TCVs). However, because the BVOJ was open, and the pressure wave caused by the TSV closure, the TBVs go to 90% open, which corresponds to a steam flow of approximately 35% Core Thermal Power. Reactor steam flow immediately. increased and reactor pressure rapidly lowered. The initial reactor level swell reached 179" Top of Active Fuel (TAF') (Turbine Trip is 175" TAP as a reference) due to the voiding swell while reactor pressure decreases. The Balance of Plant (BOP) Reactor Operator (RO) commenced driving the BVOJ closed in accordance with station procedures in an attempt to reduce the rate of pressure reduction and maintain reactor inventory. This drdves a reduction in voiding swell and a level decrease that is compounded by a significant inventory reduction due to the single element control on the 'A' Low Plow Feed Regulating Valve not being capable of providing adequate flow to compensate for this transient. As a result, Indicated reactor level rapidly lowers, and the Unit RO performs the manual SCRAM actions in accordance with station procedures. However, the automatic SCRAM was processed moments before by the Reactor Protection System (RPS) reactor low-level signal. The Unit RlO was less than one second behind the automatic SCRAM. The reactor water level reached a low point of approximately 107" TAP.

Following the reactor SCRAM, all systems operated as expected.

Following the actuation, all systems responded as expected; therefore, this event is of low safety significance.

Cause of Event

On October 12, 2014, an automatic SCRAM occurred during the reactor startup evolution following the 1 R25 refueling outage. The SCRAM occurred when a station electrician secured power to the Main Generator AVR controllers while the Main Turbine warmilng evolution was in progress. The electrician, engineer, and technician were not authorized to perform this action nor did they have procedures in the field to operate the equipment.

Additional barriers had failed in the process sequence that could have prevented this event, Including failure to follow the task management process and procedures, failure to conduct proper briefs In accordance with human performance procedures, and gaps In the planning process that resulited in an Inadequate work package. These and other failed barriers in this sequence exhibited a commonality of a failure to comply with the applicable process and procedure.

Air

he Root Cause of this event Is that Station Leadership has inconsistently reinforced Human Performance Error Reduction Tool Use and Procedure Use and Adherence. A Contributing Cause is that individuals made decisions to deviate from processes, procedures, and human performanlce tool use because they incorrectly assumed there was no risk involvedl and they wanted to complete the assigned task to meet schedules.

Corrective Actions

To address the Root Cause, Exelon took (or will take) the following actions:

1, Senior Leadership Team will review at least once per week the station performance observations (i.e., Day in the Field, Daily Observation challenges, meeting observations, etc.) for strengths and gaps in human performance error reduction tool usage and procedure use and adherence to ensure supervision is critically observing performance. Trends and specific observations/direction will be communicated to First-Line Supervisors and above on a weekly basis.

2. Generate and communicate a human perfoi'mance vision statement to the site.
3. Establish a daily, Firet-Une Supervisor time in the field expectation of at least two hours and daily observations focused on human performance tool use and procedure Usne and adherence.
4. Create a template and implement a process for the First-Line Supervisor/Manager Daily Observations and the Senior Leadership ream presentation and challenge. First-Line Supervisors or Managers will present their Daily Observation of human performance error reduction tool use and procedure use and adherence to multiple Senior Leadership Team members. The Senior Leadership Team members will engage the Pirst-.Lne Supervisors and Managers to ensure leadership team alignment and supervisor engagement in human performance and procedure use and adherence. The outcome of this interacton will be documented in a performance observatin database for that First-Une Supervisor.
5. The Station Leadership Alignment Meeting and the Leader-to-Leader meeting will have agenda items specifically to address observed site behavior for human performance and procedure use and adherence to align on observations and actions.

To address the Contributing Cause, Exelon has taken (or will take) the following actions:

1. Create and implement a Behavior Based Performance Policy to ensure a clear and consistent management approach to procedure use and adherence Issues.
2. Site management will discuss with their direct reporting personnel that the expectation is strict compliance with processes and procedures; each instance of non-compliance will be addressed consistently. These discussions are to be documented in the performance observation database or an affirmation letter.

Previous Occurrences

This was the first occurrence of the Automatic Voltage Regulator causing a Main Turbine trip, and the subsequent SCRAM at Oyster Creek. There arre historical Issue Reports (IRs) that documented deficiencies related to procedure use and adherence and the improper use of human performance tools.

NRC FORM 36eA (01-2014)

Retrieved from "https://kanterella.com/w/index.php?title=05000219/LER-2014-006-01,_Regarding_Reactor_Scram_Due_to_Decreasing_Reactor_Water_Level&oldid=5183827"