ML17289A929: Difference between revisions
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[External_Sender] TSTF-542 Issue that affects BWR/5 and BWR/6 plants Attachments: | |||
Variation Discussion.docx Michelle, We have found an issue with the TSTF-542 tr aveler that affects BWR/5 and BWR/6 plants. | Variation Discussion.docx Michelle, We have found an issue with the TSTF-542 tr aveler that affects BWR/5 and BWR/6 plants. | ||
When High Pressure Core Spray (HPCS) is being credited as the operable ECCS subsystem to meet TS 3.5.2, "Reactor Pressure Vessel Water Inventory Control," Table 3.3.5.2-1 (RPV WIC Instrument ation) requires the HPCS Level 8 function (3.a) and the HPCS manual initiation function (3.e) to be operable. However, the Level 8 function closes the HPCS injection valve and prevents injecting water into the vessel until the water level drops below the setpoint, which is below the main team lines within the vessel. If a licensee were to have an unexpec ted draining event so severe that they want to use HPCS to respond, it's unlikel y they would wait until the water level dropped that low before injecting. | When High Pressure Core Spray (HPCS) is being credited as the operable ECCS subsystem to meet TS 3.5.2, "Reactor Pressure Vessel Water Inventory Control," Table 3.3.5.2-1 (RPV WIC Instrument ation) requires the HPCS Level 8 function (3.a) and the HPCS manual initiation function (3.e) to be operable. However, the Level 8 function closes the HPCS injection valve and prevents injecting water into the vessel until the water level drops below the setpoint, which is below the main team lines within the vessel. If a licensee were to have an unexpec ted draining event so severe that they want to use HPCS to respond, it's unlikel y they would wait until the water level dropped that low before injecting. | ||
Revision as of 11:27, 26 April 2019
| ML17289A929 | |
| Person / Time | |
|---|---|
| Site: | Technical Specifications Task Force |
| Issue date: | 10/16/2017 |
| From: | Mann B D Excel Services Corp |
| To: | Honcharik M C Office of Nuclear Reactor Regulation |
| Honcharik M C | |
| Shared Package | |
| ml17289A902 | List: |
| References | |
| Download: ML17289A929 (1) | |
Text
From: Brian Mann <Brian.Mann@excelservices.com> Sent: Monday, October 16, 2017 9:26 AM To: Honcharik, Michelle Cc: Whitman, Jennifer; Cusumano, Victor
Subject:
[External_Sender] TSTF-542 Issue that affects BWR/5 and BWR/6 plants Attachments:
Variation Discussion.docx Michelle, We have found an issue with the TSTF-542 tr aveler that affects BWR/5 and BWR/6 plants.
When High Pressure Core Spray (HPCS) is being credited as the operable ECCS subsystem to meet TS 3.5.2, "Reactor Pressure Vessel Water Inventory Control," Table 3.3.5.2-1 (RPV WIC Instrument ation) requires the HPCS Level 8 function (3.a) and the HPCS manual initiation function (3.e) to be operable. However, the Level 8 function closes the HPCS injection valve and prevents injecting water into the vessel until the water level drops below the setpoint, which is below the main team lines within the vessel. If a licensee were to have an unexpec ted draining event so severe that they want to use HPCS to respond, it's unlikel y they would wait until the water level dropped that low before injecting.
Instead, they could manually start the HPCS pump and defeat the Level 8 interlock to open the injecti on valve, rendering the Level 8 function inoperable. It doesn't make sense to us to r equire the Level 8 function if in most cases the licensee would make it i noperable to perform the function.
We have drafted the attached variation discussion which removes the HPCS Level 8 function and HPCS manual initiation function from Table 3.3.5.2-1.
The justification for crediting manually starting the HPCS pump and opening the valve is similar to the variations written by plants that do not hav e an ECCS manual initiation function in their design.
We'd like to have a call with the NRC this week to discuss the variation. We believe it would be beneficial to the industry and the NRC to agree on a standard description.
Brian
Brian D. Mann Vice President of Indus try Programs and Services EXCEL Services Corporation Mobile (804) 339-7034 Main (301) 984-4400 E-mail: brian.mann@excelservices.com Web: www.excelservices.com Web: www.nukapedia.com