ML21322A051

Paragon Energy Solutions, LLC, P21-09282021, Rev. 0, Final Notification of a Deviation with Inverter Assembly (Model NLI-072034-CSI-K-5-A)

ML21322A051
Person / Time
Site:	Peach Bottom, Brunswick, Limerick
Issue date:	10/27/2021
From:	Bolt T Paragon Energy Solutions
To:	Office of Nuclear Reactor Regulation
References
P21-09282021, Rev. 0
Download: ML21322A051 (4)

Text

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Paragon Date: 10/27/2021 To: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555 Fax Number (301) 816-5151 10CFR Part 21 Formal Notification: P21-09282021, Rev. 0

Subject:

Final Notification of a Deviation with Inverter Assembly (Model NLI-072034-CSI-K-5-A)

Pursuant to 10CFR 21.21 (d) (3) (ii), Paragon Energy Solutions is providing written notification of the identification of a deviation.

On the basis of our evaluation dated 9/3/2021, it was determined that Paragon did not have sufficient information to determine if the subject condition would, or has, created a Substantial Safety Hazard or would have created a Technical Specification Safety Limit violation as it relates to the subject plant applications.

Exelon - Limerick and Peach Bottom were notified on 9/3/2021.

Duke - Brunswick was notified on 9/7/2021.

On 9/28/2021, Exelon Peach Bottom provided information indicating that the failure of the unit in service could cause a substantial safety hazard in their application.

The following information is required per 10CFR 21.21 (d) (4).

(i) Name and address of the individual or individuals informing the Commission.

Tracy Bolt, Chief Nuclear Officer Paragon Energy Solutions, LLC 7410 Pebble Drive Ft. Worth, TX 76118 (ii) Identification of the facility, activity, or the basic component supplied for such facility or such activity within the United States which fails to comply or contains a defect.

Inverter Assembly 1000VA NLI PIN: NLI-072034-CSI-K-5-A Exelon - Peach Bottom, Limerick Duke - Brunswick Paragon Energy Solutions 7410 Pebble Drive* Fort Worth, Texas* 76118 81 7-284-0077

• Fax 817-590-0484 Page 1 of 4

(iii) Identification of the firm constructing or supplying the basic component which fails to comply or contains a defect.

Components were originally supplied by Nuclear Logistics, LLC 7410 Pebble Drive, Fort Worth Texas 76118 (iv) Nature of defect or failure to comply and the safety hazard which is* created or could be created by such defect or failure to comply.

Paragon's investigation of the failed units has concluded that Absopulse Model CSI-K-B-Q9573-l units manufactured with transformer TR121Dl25/202A installed within their DC-DC converters, pose a higher risk of failing randomly during operation. These transformers were used in some of the post 2015 Absopulse inverter designs where the heat sink mounted rectifiers are being exposed to voltage levels beyond their design limits. It is our belief that prolonged operation could cause premature failure of the rectifier at indeterminate operational intervals.

The deviation relates to failure of the installed Absopulse 1OOOVA inverter (Model CSI-K-B-Q9573-1 ). The extent of condition is currently limited to Absopulse inverters manufactured or repaired in 2015 and later. As stated above, the root cause of the failure has been determined to be the transformer PIN: TR121D125/202A. It is not an issue with the transformer in general, just this specific transformer in this application. Of the post 2015 Absopulse Model CSI-K-B-Q9573-1 inverter design, the identified failures in the industry are low compared to the number of units that have been supplied. Paragon was able to run testing on an additional post 2015 unit that was on site. The additional unit did not exhibit the same high voltage spikes which were witnessed on the two failed Peach Bottom units. The reason for this is isolated to a variance in transformer model within the post 2015 converter designs.

The two failed Peach Bottom units utilized transformer model TRI 21 D 125/202A which is approximately a 4x step-up transformer, while the unit which does not exhibit high voltage spikes utilized model TR121D125/115A, which is approximately a 2.5x step-up transformer. It is Paragon's belief that post 2015 inverters, that have the TR121D125/202A (4x step-up), pose a higher risk of failing randomly during operation in this specific application.

The safety function of the DC/DC converter output rectifier is to provide the appropriate voltage output to downstream loads.

Although the failed component is the DC-DC converter output rectifiers (ROHM PIN: SCS210KE2) the root cause of the DC/DC con,verter failure is due to the 4X step-up transformer model TR121D125/202A.

(v) The date on which the information of such defect or failure to comply was obtained.

On 9/28/2021, Exelon Peach Bottom provided information indicating that the failure of the unit in service could cause a substantial safety hazard in their application if left uncorrected.

P21-09282021 Rev. 0 Page 2 of 4

(vi) In the case of a basic component which contains a defect or fails to comply, the number and location of these components in use at, supplied for being supplied for, or may be supplied for, manufactured, or being manufactured for one or more facilities or activities subject to the regulations in this part.

The following table identifies the units that were supplied or refurbished after 2015 Plant Client PO# Project Number NLIModel Qty Type of supply Peach Bottom 90 065497 351021814 NLI-072034-CSI-K-5-A 4 New Limerick 00606902 351026560 NLI-072034-CSI-K-5-A 2 New Limerick 00663381 351027091 NLI-072034-CSI-K-5-A 2 New Limerick 00704133 351029204 NLI-072034-CSI-K-5-A 2 New Brunswick 03050825 351026846 NLI-072034-CSI-K-5-A 6 New Brunswick 03052088 351026941 NLl-072034-CSI-K-5-A 1 New Limerick 90 082966 351024754 NLI-072034-CSI-K-5-A 1 Refurbished Limerick 90 083949 351024926 NLI-072034-CSI-K-5-A I Refurbished Limerick 90 086799 351025299 NLI-072034-CSI-K-5-A 1 Refurbished Limerick 00654374 351027748 NLI-072034-CSI-K-5-A 1 Refurbished Limerick 00684578 351028652 NLl-072034-CSI-K-5-A 1 Refurbished Limerick 00697845 351029024 NLI-072034-CSI-K-5-A 1 Refurbished Peach Bottom 00694785 351028920 NLI-072034-CSI-K-5-A 1 Refurbished (vii) The corrective action which has been, is being, or will be taken; the name of the individual or organization responsible for the action; and the length of time that has been or will be taken to complete the action.

This issue has been entered into the Paragon Non-Conformance and Corrective Action Program. Paragon has communicated with the commercial OEM regarding their corrective actions to prevent the recurrence of this issue in future units supplied to Paragon.

Paragon Corrective Actions:

• Paragon has created an inspection procedure for existing supplied units.

• The identified plants have been provided the inspection procedure to help identify suspect inverters that were built or refurbished after 2015 that may contain the 4x step up transformer.

• Paragon will work with the identified plants to rework the inverter assemblies that require the transformer replacement. Expected completion: at the plant's discretion

• The assembly instructions and/or Test plans will include an inspection to ensure the correct transformer is installed. Expected completion: by 11/30/2021 P21-09282021 Rev. 0 Page 3 of 4

(viii) Any advice related to the defect or failure to comply about the facility, activity, or basic component that has been, is being, or will be given to purchasers or licensees.

Paragon recommends the following:

Screen the generation of Absopulse inverter installed in your equipment through visual inspection. Paragon has written and provided Inspection Procedure JP.:NLJ-072034-CSI-K-5-A to aid the plants with their screening process.

If screening identifies the problematic transformer or if screening activities are not available at the plant; remove, segregate and return post 2015 supplied units.

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Chief Nuclear Officer Paragon Energy Solutions 817-284-0077 tbolt@paragones.com P21-09282021 Rev. 0 Page 4 of 4