05000499/LER-2019-001, Equipment Clearance Order Error Leads to Loss of Primary Containment Integrity

Equipment Clearance Order Error Leads to Loss of Primary Containment Integrity

ML19308B381
Person / Time
Site:	South Texas
Issue date:	11/04/2019
From:	Schaefer M South Texas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NOC-AE-19003691 LER 2019-001-00
Download: ML19308B381 (8)

LER-2019-001, Equipment Clearance Order Error Leads to Loss of Primary Containment Integrity

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 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)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)
4992019001R00 - NRC Website

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Nuclear Operating Company Soutfl Texas Project Electric Generating Station P.O. Box 289 Wadswortfl, Texas 77483 November 4, 2019 NOC-AE-19003691 10 CFR 50.73 Attention: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 South Texas Project Unit2 Docket No. STN 50-499 Licensee Event Report 2019-001-00 Equipment Clearance Order Error Leads to Loss of Primary Containment Integrity Pursuant to reporting requirements of 1 O CFR 50. 73(a)(2)(i)(B), 10 CFR 50. 73(a)(2)(v)(C), and 10 CFR 50.73(a)(2)(v)(D), STP Nuclear Operating Company hereby submits the attached South Texas Project Unit 2 Licensee Event Report 2019-001-00.

The event did not have an adverse effect on the health and safety of the public.

There are no commitments in this submittal.

If there are any questions, please contact Tim Hammons at 361-972-7347 or me at 361-972-7888.

Attachment: Unit 2 LER 2019-001-00, Equipment Clearance Order Error Leads to Loss of Primary Containment Integrity STI: 34937611

cc:

Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 1600 E. Lamar Boulevard Arlington, TX 76011-4511 NOC-AE-19003691 Page 2 of 2

Attachment Unit 2 LER 2019-001-00 NOC-AE-19003691 Attachment Equipment Clearance Order Error Leads to Loss of Primary Containment Integrity

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

, the NRC may not conduct or sponsor, and a person is not required to respond to, the infonmation collection.

3.Page South Texas Unit 2 05000499 1

OF 5

4. Title Equipment Clearance Order Error Leads to Loss of Primary Containment Integrity

5. Event Date

6. LER Number

7. Report Date

8. Other Facilities Involved I

Sequential I

Rev Facility Name Docket Number Month Day Year Year Month Day Year N/A 05000 Number No.

Facility Name Docket Number 09 03 2019 2019 -

001 00 11 04 2019 N/A 05000

9. Operating Mode

11. This Report is Submitted Pursuant to the Requirements of 1 O CFR §: (Check all that apply)

• 20.2201(b)

D 20.2203(a)(3)(i)

• 50.73(a)(2)(ii)(A)

D 50.73(a)(2)(viii)(A)

• 20.2201(d)

D 20.2203(a)(3)(ii)

• 50.73(a)(2)(ii)(B)

D 50.73(a)(2)(viii)(B) 1 D 20.2203(a)(1)

D 20.2203(a)(4)

D 50.73(a)(2)(iii)

D 50.73(a)(2)(ix)(A)

D 20.2203(a)(2)(i)

• 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)

• 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 50.36(c)(2)

D 50.73(a)(2)(v)(B)

D 73.71(a)(5)

D 20.2203(a)(2)(iv)

D 50.46(a)(3)(ii)

!81 50.73(a)(2)(v)(C)

D 73.77(a)(1) 100 D 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A)

!81 50.73(a)(2)(v)(D)

D 73.77(a)(2)(ii)

D 20.2203(a)(2)(vi)

[81 50. 73(a)(2)(i)(B)

D 50.73(a)(2)(vii)

D 73.77(a)(2)(iii)

)

• -/;

,*,*, <,;/>

-,,,.-2' -*

• 50.73(a)(2)(i)(C)

D Other (Specify in Abstract below or in summary of the event Timeline (Note: All times are Central Standard Time):

July 10, 2019 [1515]: Containment Air Sample Outside Reactor Containment Isolation Valve 2-AP-FV-2456 declared inoperable due to excessive seat leakage.

YEAR 2019 SEQUENTIAL NUMBER

- 001 August 1, 2019: ECO revision prepared for replacement of Containment Isolation Valve 2-AP-FV-2456.

August 26, 2019: ECO revision approved by the Technical Reviewer (Licensed Senior Reactor Operator).

September 2, 2019 [1836]: ECO revision approved by the Issuing Authority (Licensed Senior Reactor Operator). The Technical Reviewer and Issuing Authority are separate individuals.

September 3, 2019 [1300 - 1315]: Event Date. Containment Hydrogen Monitoring Sample Inlet Test REV NO.

- 00 Valve 2-CM-0005 [TV] between the containment wall and a containment isolation valve inside the containment building is opened as directed by the ECO. Opening of this valve coupled with the inoperability of Containment Isolation Valve 2-AP-FV-2456 created a breach of containment.

September 5, 2019 [2115]: Discovery Date. Control Room staff discovered Technical Specifications 3.6.3 and 3.6.1.1 associated with containment penetration M-82D were not being met.

September 5, 2019 [2322]: Valve 2-CM-0005 closed and Technical Specification compliance restored.

F.

Method of discovery

The event was discovered by a Unit Supervisor approving a release revision (work completion) of the ECO.

II. Component failures

A

Failure Mode, mechanism, and effects of failed component

The failed component in this event is containment penetration M-82D [PEN]. The safety function (maintain containment integrity) of containment penetration M-82D could not be met with both an inside and outside containment isolation valve open.

B.

Cause of component failure

Containment penetration M-82D failure was due to an error in an ECO which went undetected by two utility licensed SR Os as a result of their failure to recognize at-risk behaviors and apply appropriate human performance tools.

C. Systems or secondary functions that were affected by failure of components with multiple functions No additional systems were affected by the containment penetration failure.

D.

Failed component information

Reactor Containment Building [NH]

Penetration [PEN]

Ill. Analysis of the event A.

Safety system responses that occurred No safety systems were required to respond as a result of this event.

B.

Duration of safety system inoperability

YEAR 2019 SEQUENTIAL NUMBER

- 001 The duration of the containment breach was approximately 58 hours6.712963e-4 days <br />0.0161 hours <br />9.589947e-5 weeks <br />2.2069e-5 months <br /> [September 3, 2019 (1300) to September 5, 2019 (2322)].

C. Safety consequences and implications

REV NO.

- 00 This event had insignificant safety consequences because the containment breach was disconnected from the Reactor Coolant System (RCS) by a series of closed valves for the duration of the event. Additionally, the lines to the vent and test connection valves which were found to be open, as well as the main line connecting them and passing through 2-FV-2456, all have a one-inch inner diameter. Containment breaches of less than a three-inch diameter do not lead to a large radiation release. The event did not result in any offsite release of radioactivity or increase of offsite dose rates, and there were no personnel injuries or damage to any other safety-related equipment associated with this event.

Therefore, there was no adverse effect on the health and safety of the public.

IV. Cause of the event

The root cause of the event was personnel error related. Individuals involved in the technical review and approval of the ECO failed to recognize at-risk behaviors and apply appropriate Human Performance (HU) tools. At-risk behaviors not considered include:

Making assumptions - The Issuing Authority stopped when the individual saw "Swap Tag" in a note field on a line item of the ECO revision and did not perform a detailed review of the remaining ECO line items. As a result, the Issuing Authority made a wrong assumption that an inside containment isolation valve would remain closed.

Believing the source of information is absolutely reliable - The Technical Reviewer (new to this assignment) assumed that ECOs would be technically sound and that the technical review would be more of a higher-level review.

Thinking the task is routine or simple - Both the Technical Reviewer and Approver of the ECO stated they viewed the ECO as routine or simple.

Appropriate error reduction tools not used by both individuals include Questioning Attitude and Peer Review/Collaboration.

V. Corrective actions

Completed - Closed valve 2-CM-0005 to restore containment integrity and implemented the site consistency matrix (disciplinary) process for responsible personnel.

Planned - Procedure changes and modification to the software that controls the ECO process. The procedure changes will:

YEAR 2019 SEQUENTIAL NUMBER

- 001 (1) Require that the Technical Reviewer and the Issuing Authority be separate SROs for the issuance (initial) of all ECOs that ensure Technical Specification compliance.

(2) Add guidance to require SROs that use ECOs to ensure Technical Specification compliance on Operability Assessments to sign on to the ECO as an Acceptor specifically for Technical Specification compliance.

(3) Include steps and acceptor checklist items for the ECO job acceptor function for Operations use when ensuring initial and continuing Technical Specification compliance. The ECO acceptor SHALL be a separate SRO from the SRO who is the Issuing Authority and their sole function/ purpose is to ensure Technical Specification compliance. Also include direction to ensure the ECO is designated as being used for Technical Specification compliance.

The software modifications will implement a business rule in the ECO application to ensure that the ECO acceptor is a separate SRO from the SRO who is the Issuing Authority for ECOs used to maintain Technical Specification compliance.

VI. Previous similar events

REV.

NO.

- 00 An operating experience review identified a similar event at South Texas Unit 2 on June 28, 2000. Licensee Event Report (LER) 2000-003-00, Reactor Containment Building Penetration M-85 Not Properly Isolated, was attributed to failure to meet management expectations associated with work practices. The Shift and Unit Supervisors are ultimately responsible for maintaining the unit in compliance with Technical Specifications. In the LER 2000-003-00 event, neither the Shift nor the Unit Supervisor verified the ECO to ensure Technical Specification compliance due to overconfidence in the Work Start Authority's capability. The fact that the valve was already tagged to comply with Technical Specifications caused the Shift and Unit Supervisors to perceive this activity to be a low-risk evolution. In addition, the Shift and Unit Supervisors are responsible for ensuring the use of peer checks for Technical Specification compliance and no peer checks for the ECO were performed. Corrective actions included Operations management reinforcing expectations to Operations personnel regarding roles and responsibilities for Technical Specification compliance, peer checking, and the use of error reduction tools.

The LER 2000-003-00 event is very similar to the event depicted in this LER. Both events are attributed to human performance errors. Each event involves inadequate reviews of an ECO resulting in non-compliance with Technical Specifications. The ECO review inadequacies in each event are attributed to not using proper error reduction or human performance tools, including peer checking. LER 2000-003-00 corrective actions were exclusively focused on behavior-based solutions (i.e., management reinforcing expectations to subordinates), whereas corrective actions for this event are focused on both behavior-based solutions (counseling and disciplinary action) and process-based solutions (procedure and software changes). Page _5_of_5_