ML22108A165

Enclosure 2 - Timeline of Event

ML22108A165
Person / Time
Site:	Diablo Canyon
Issue date:	05/03/2022
From:	Office of Nuclear Reactor Regulation
To:
Zachary Hollcraft NRR/DRO/IRIB 415-0504
Shared Package
ML22123A188	List: ML22108A165 ML22108A166 ML22108A167 ML22109A179
References
Download: ML22108A165 (2)

Text

Timeline of Events Date Event 20APR2009 Operating experience on external corrosion under insulation posted to Institute of Nuclear Power Operations (INPO) database (proprietary information).

19APR2010 Operating experience on external corrosion under insulation posted to INPO database (proprietary information).

14NOV2013 NRC issues LR-ISG-2012-02, Aging Management of Internal Surfaces, Fire Water Systems, Atmospheric Storage Tanks, and Corrosion under Insulation. It is not applicable to Diablo Canyon Nuclear Power Plant (DCNPP) because DCNPP is not in its extended license period.

1JAN2020 Coronavirus Disease 2019 (COVID-19) public health emergency (PHE) declared.

10JAN2020 Resident inspectors tour affected Unit 2 pipe space for 12 minutes 15FEB2020 Resident inspectors tour affected Unit 2 pipe space for 8 minutes 9MAR2020 Resident inspectors tour affected Unit 2 pipe space for 9 minutes 16MAR2020 NRC staff ordered to full telework due to the COVID-19 PHE.

19MAR2020 The California Governor issues a stay-at-home order; resident inspectors are exempt under Federal critical infrastructure classification.

19MAR2020 Initial resident office site coverage guidance is issued. Residents are directed to visit the site once every 3 days in accordance with the guidance in Inspection Manual Chapter 2515, Light-Water Reactor Inspection ProgramOperations Phase.

31MAR2020 The NRC Office of Nuclear Reactor Regulation hosts an inspector townhall, and the Office Director makes clear that inspectors priority should be their personal safety with respect to COVID-19.

6APR2020 Updated guidance on resident site coverage is provided through a memorandum (ADAMS Accession No. ML20097E538, publicly available at:

Guidance For Resident Inspectors l NRC.gov) that reiterates the 3-day requirement and provides some additional guidance.

13APR2020 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> charged to Inspection Procedure (IP) 71111.04, Equipment Alignment.

13APR2020 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, 21 minutes logged in the vicinity of Unit 1 or 2 auxiliary feedwater (AFW) equipment.

14APR2020 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> charged to IP 71111.04.

20APR2020 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> charged to IP 71111.04.

20APR2020 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, 44 minutes logged in the vicinity of Unit 1 or 2 AFW equipment.

27APR2020 0.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> charged to IP 71111.04.

27APR2020 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, 2 minutes logged in the vicinity of Unit 1 or 2 AFW equipment.

8JUN2020 Resident inspectors tour Unit 2 affected pipe space for 8 minutes.

8JUL2020 Resident inspectors tour Unit 2 affected pipe space for 6 minutes.

17JUL2020 Unit 2 shut down due to hydrogen leak in main turbine generator; AFW placed in service and pipe pressurized.

22JUL2020 DCNPP Integrated Inspection Report 2020002 issued, documenting complete system walkdown.

23JUL2020 Leak discovered on elbow downstream of LCV-111, SG 2-2 AFW Control Valve; Unit 2 cools down from Mode 3 to Mode 4 to meet Limiting Condition for Operation 3.7.5.D.2.

30JUL2020 DCNPPs extent of condition inspection discovers seven AFW pipe locations requiring repair to the standards of the American Society of Mechanical Engineers.

Enclosure 2

Timeline of Events Date Event 31JUL2020 Unit 2 declares AFW operable.

3AUG2020 Unit 2 returned to full power.

29OCT2020 DCNPP Integrated Inspection Report 2020003 issued, documenting green finding.

25MAR2022 OIG CASE No.20-025 special inquiry issued.

Note 1: The gray portion is the period within the scope of the system alignment inspection.

Note 2: Inspectors toured the plant on multiple occasions during the period in question, this timeline only highlights those times and areas pertinent to the OIG inquiry.

2