L-MT-22-012, Special Report for the Bypass of the Offgas Treatment Storage System

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Special Report for the Bypass of the Offgas Treatment Storage System
ML22076A104
Person / Time
Site: Monticello Xcel Energy icon.png
Issue date: 03/15/2022
From: Domingos C
Northern States Power Company, Minnesota, Xcel Energy
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
L-MT-22-012, ODCM-03-01
Download: ML22076A104 (3)


Text

fl Xcel Energy* 2807 West County Road 75 Monticello, MN 55362 March 15, 2022 L-MT-22-012 ODCM-03.01 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Monticello Nuclear Generating Plant Docket No. 50-263 Renewed Facility Operating License No. DPR-22 Monticello Nuclear Generating Plant (MNGP) Special Report Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter "NSPM"), hereby submits a special report in accordance with the Monticello Nuclear Generating Plant Offsite Dose Calculation Manual (ODCM) ODCM-03.01 Section 2.4.3. This report provides notification that the Offgas Treatment Storage System was bypassed for more than seven days.

- - - - Summary-of-Gommitments- -

Tazc no new commitments and no revisions to existing commitments.

Christopher P. Doming Site Vice President, Monticello and Prairie Island Nuclear Generating Plants Northern States Power Company - Minnesota Enclosure cc: Administrator, Region Ill, USNRC Project Manager, Monticello, USNRC Resident Inspector, Monticello, USNRC State of Minnesota

ENCLOSURE MONTICELLO NUCLEAR GENERATING PLANT SPECIAL REPORT FOR THE BYPASS OF THE OFFGAS TREATMENT STORAGE SYSTEM

Background

The Monticello Nuclear Generating Plant (MNGP) is currently upgrading the hydrogen and oxygen (H2O2) Monitoring System due to obsolescence . Installation of new 'B' H2O2 Monitoring System equipment was completed and on February 14, 2022, at 0314 hours0.00363 days <br />0.0872 hours <br />5.191799e-4 weeks <br />1.19477e-4 months <br /> the Offgas Treatment Storage System was bypassed to place the 'B' hydrogen recombiner in service and begin pre-operational testing.

The Offgas Treatment Storage System was bypassed with the 'B' Recombiner in service and with the 'B' H2O2 Monitoring System nonfunctional in accordance with ODCM-03.01 Section 2.4.1.D.

ODCM-03.01 section 2.4.3.A requires the following:

With gaseous waste being discharged for more than seven (7) days with an average holdup time of less than 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />, prepare and submit within 30 days a

- - - -~SReciaLr~p_prt to the Commissio_.n__,____ _ _ _ __

On February 21, 2022 at 0314 the 'B' Offgas Treatment Storage System was bypassed for more than seven days. At no time while the Offgas Treatment Storage System was bypassed were the gaseous effluent administrative limits exceeded.

Identification of the Non-Functional Equipment or Subsystems and the Reason for Non-Functionality On February 19, 2022, during pre-operational testing it was identified that drain traps were not included as part of the modification to prevent calibration gas from backflowing from the analyzer being calibrated to the in-service analyzers. This prevented completion of the testing and required the installation of additional equipment.

Actions to Restore Functionality The necessary equipment needed to perform the calibration of the 'B' H2O2 Monitoring System modification was installed, successfully tested, and turned over to Operations on February 25, 2022. The 'B' H2O2 Monitoring System was subsequently declared functional. The Offgas Treatment Storage System was restored at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> on February 25 , 2022 and the ODCM-03.01 action statement was exited.

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Actions to Prevent Reoccurrence The changes to prevent backflow of calibration gas were incorporated into the 'A' H202 Monitoring System design and installation instructions. In addition, the engineering organization completed validation to ensure that the installed configuration matches the configuration during factory acceptance testing .

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