ML13164A130
| ML13164A130 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 04/30/2013 |
| From: | - No Known Affiliation |
| To: | Division of Operating Reactor Licensing |
| References | |
| Download: ML13164A130 (8) | |
Text
WBN2Public Resource From: Boyd, Desiree L [dlboyd@tva.gov]
Sent: Tuesday, April 30, 2013 11:00 AM To: Hon, Andrew; Epperson, Dan; Quichocho, Jessie; Poole, Justin Cc: Arent, Gordon; Hamill, Carol L; Boyd, Desiree L
Subject:
TVA letter to NRC_04-29-2013_Potential Instrumentation Line Slope Issue Attachments: 04-29-2013_Potential Instrumentation Line Slope Issue_Final.pdf Please see attached TVA letter that was sent to the NRC today.
Thank You
~*~*~*~*~*~*~*~*~*~*~
Désireé L. Boyd WBN Unit 2 Licensing dlboyd@tva.gov 423-365-8764 NOTICE: This electronic message transmission contains information which may be TVA SENSITIVE, TVA RESTRICTED, or TVA CONFIDENTIAL. Any misuse or unauthorized disclosure can result in civil penalties. If you are not the intended recipient, be aware that any disclosure, copying, distribution or use of the content of this information is prohibited. If you have receive this communication in error, please notify me immediately by e-mail and delete the original message.
1
Hearing Identifier: Watts_Bar_2_Operating_LA_Public Email Number: 810 Mail Envelope Properties (7AB41F650F76BD44B5BCAB7C0CCABFAF41FDA061)
Subject:
TVA letter to NRC_04-29-2013_Potential Instrumentation Line Slope Issue Sent Date: 4/30/2013 10:59:43 AM Received Date: 4/30/2013 10:59:48 AM From: Boyd, Desiree L Created By: dlboyd@tva.gov Recipients:
"Arent, Gordon" <garent@tva.gov>
Tracking Status: None "Hamill, Carol L" <clhamill@tva.gov>
Tracking Status: None "Boyd, Desiree L" <dlboyd@tva.gov>
Tracking Status: None "Hon, Andrew" <Andrew.Hon@nrc.gov>
Tracking Status: None "Epperson, Dan" <Dan.Epperson@nrc.gov>
Tracking Status: None "Quichocho, Jessie" <Jessie.Quichocho@nrc.gov>
Tracking Status: None "Poole, Justin" <Justin.Poole@nrc.gov>
Tracking Status: None Post Office: TVANUCXVS2.main.tva.gov Files Size Date & Time MESSAGE 754 4/30/2013 10:59:48 AM 04-29-2013_Potential Instrumentation Line Slope Issue_Final.pdf 100282 Options Priority: Standard Return Notification: No Reply Requested: Yes Sensitivity: Normal Expiration Date:
Recipients Received:
Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381-2000 April 29, 2013 CDR-50-391/2013-02 10 CFR 50.55(e)
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 2 NRC Docket No. 50-391
Subject:
WATTS BAR NUCLEAR PLANT (WBN) UNIT 2 - CONSTRUCTION DEFICIENCY REPORT 50-391/2013 INSTRUMENT SENSE LINE SLOPE ISSUE - INTERIM REPORT The purpose of this letter is to provide the interim Construction Deficiency Report (CDR) 391/2013-02 regarding a condition TVA has identified which has the potential to be a significant (programmatic) breakdown in the instrument sense line installation program and, thus, a potential breakdown in TVAs quality assurance program. Walkdowns completed to date have not identified any specific examples where instrument line slopes as installed would have prevented the associated instruments from performing their intended safety functions.
Until these walkdowns and/or evaluations are completed on affected systems, the potential exists to identify a substantial safety hazard. Initial notification was made on April 1, 2013, via Event Notification No. 48871.
The apparent cause of this condition involves a misinterpretation of construction procedure 25402-000-GPP-0000-N3401, Instrument and Instrument Line Installation, which lacked proper detail to define the boundary of the sense line from the panel isolation valve to process connection including the root valve. Further details of this condition can be found in the interim CDR 391/2013-02 provided in Enclosure 1. Prior to system turnover to Plant Operations, TVA will complete the required walkdowns and/or evaluations of this condition and correct any identified deficiencies. TVAs system turnover process will prevent equipment and components affected by this condition from being turned over to Plant Operations prior to the condition identified being corrected.
U.S. Nuclear Regulatory Commission Page 3 April 29, 2013 bcc (Enclosures):
Jessie Quichocho U.S. Nuclear Regulatory Commission MS 08G9A One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 Fred Brown, Deputy Regional Administrator for Construction U. S. Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, Georgia 30303-1257
ENCLOSURE 1 WATTS BAR NUCLEAR PLANT (WBN) UNIT 2 REGARDING INSTRUMENT SENSE LINE SLOPE CONDITION 10 CFR 50.55(e) CONSTRUCTION DEFICIENCY REPORT (CDR) 50-391/2013-02 FIRST INTERIM REPORT DESCRIPTION OF DEFICIENCY TVA has identified a condition which has the potential to be a significant (programmatic) breakdown in the instrument sense line installation program and, thus, a potential breakdown in TVAs quality assurance program. Specifically, it has been determined that a condition exists where certain portions of the instrument line installations in multiple systems have not been completely inspected to ensure proper slope requirements (1/4 inch per foot) have been met. Inadequate sense line slope could result in the degradation of the associated safety-related instrument due to the effects of air entrapment which could adversely affect the accuracy or time response of the instrument or cause noise.
Walkdowns completed to date have not identified any specific examples where instrument line slopes as installed would have prevented instruments from performing their intended safety functions. Until these walkdowns and/or evaluation are completed, the potential exists for a substantial safety hazard determination being identified.
Therefore, this condition is conservatively being reported in accordance with 10 CFR 50.55(e). Initial notification was made on April 1, 2013, via Event Notification No. 48871.
The issues documented in CDR 50-391/2013-02 are captured in TVAs corrective action program as Problem Evaluation Report (PER) 680826.
CAUSE OF THE DEFICIENCY The apparent cause for PER 680826 involves a misinterpretation of construction procedure 25402-000-GPP-0000-N3401, Instrument and Instrument Line Installation.
The construction procedure lacked proper detail to define the boundary of the sense line from the panel isolation valve to the process connection including the root valve.
The standard Engineering Document Construction Release (EDCR) work scope statement for defining the sense line boundary is Sense line connection from the process connection (e.g. root valve) to the panel isolation valve. However, the manner in which construction procedure 25402-000-GPP-0000-N3401 was written could be interpreted to mean that the required slope inspection did not include the root valve.
TVA believes the misinterpretation is a more recent condition rather than a historical one. Early in the project, work was performed by Knowledge, Skill and Rule-based personnel. The Knowledge was developed through design review meetings that were conducted for the EDCRs prior to issuance. These meetings provided the expectations E1-1
and level of detail needed to resolve the issues related to the Instrument Line corrective action plan through extensive walkdowns involving construction and design personnel.
As the project progressed, the Skill and Rule base traits have remained. However, the Knowledge base has been diminished given the length of time that elapses between the issuance of design packages and the work that takes place to complete their implementation.
SAFETY IMPLICATIONS No substantial safety hazard examples have been identified to date. However, until further walkdowns and/or evaluations have been completed, the potential exists for a substantial safety hazard determination being identified due to this condition. Once the final safety significance of this condition is determined, TVA will provide a final CDR for this condition.
CORRECTIVE ACTIONS
- 1. Procedure 25402-000-GPP-0000-N3401, Instrument and Instrument Line Installation, has been revised to identify the sense line boundary from the process connection through the root valve to the panel isolation valve.
- 2. Training to the above revised procedure has been provided to applicable Field Engineers, Planners, and Design personnel to eliminate any Knowledge gap.
- 3. The standard statement in the EDCRs discussed above will be removed from each EDCR through approved procedures for revising EDCRs.
- 4. Prior to system turnover to Plant Operations, TVA will complete the required walkdowns and/or evaluations of this condition and correct any identified deficiencies. TVAs system turnover process will prevent equipment and components affected by this condition from being turned over to Plant Operations prior to the condition identified being corrected.
E1-2
ENCLOSURE 2 LIST OF COMMITMENTS
- 1. The standard EDCR work scope statement for defining the sense line boundary will be removed.
This action will be completed by May 30, 2013.
- 2. Prior to system turnover to Plant Operations, TVA will complete the required walkdowns and/or evaluations of this condition and correct any identified deficiencies. TVAs system turnover process will prevent equipment and components affected by this condition from being turned over to Plant Operations prior to the condition identified being corrected.
E2-1