ML20205J152
| ML20205J152 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 01/23/1986 |
| From: | Murphy W VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Muller D Office of Nuclear Reactor Regulation |
| References | |
| FVY-86-6, GL-84-07, GL-84-7, NUDOCS 8601300109 | |
| Download: ML20205J152 (7) | |
Text
e-VERMONT YANKEE NUCLEAR POWER CORPORATION FVY 86-6 RD 5, Box 169, Ferry Road, Brattleboro, VT 05301
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ENGINEERING OFFICE 1671 WORCESTER ROAD FRAMINGHAM. MASSACHUSETTS 01701 TELEPHONE 617-872-4100 January '23, 1986 U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Attn:
Office of Nuclear Reactor Regulation Mr. Daniel R. Muller, Director BWR Project Directorate #2 Division of BWR Licensing
References:
a)
License No. DPR-28 (Docket No. 50-271) b)
Letter, USNRC to All Licensees of Boiling Water Reactors (Generic Letter 84-07), NVY 84-53, dated 3/14/84 c)
Letter, VYNPC to USNRC, FVY 85-36, dated 4/22/85
Dear Sir:
Subject:
Scope of Vermont Yankee's Recirculation System Pipe Replacement Program This letter transmits an updated issue of the description of the Vermont Yankee recirc pipe replacement project, originally' transmitted via Reference c).
The revised areas are sidelined for clarity.
Should you have any questions, please feel free to contact us.
Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION A4 Warren P. Murphy Vice President and Manager of Operations
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e ATTACHMENT 1 i
1.0 INTRODUCTION
1.1 Purpose l
This document describes the activities and system design associated.
with the replacement of the Recirculation System and portions of the ~
Residual Heat Removal (RHR) System at Vermont Yankee.
1.2 Scope This submittal describes the engineering, design, procurement, re-moval, and installation of the Recirculation and RHR Systems.
2.0 PROJECT DESCRIPTION This project task is to replace existing 304 stainless steel material with
. controlled chemistry 316 material for improved IGSCC-resistance.
2.1 Overall Oraanization The project is organized with Vermont Yankee providing overall direction to the engineers and contractors involved. A dedicated project team has been formed with responsibility for the engi-neering, construction, design, procurement, disposal, and quality assurance activities for the project.
Each engineer or contractor will perform his work under his quality assurance program, which will be reviewed and approved by the pro-ject team.
The replacement will.be performed as an Engineering Design Change Request (EDCR) under the Yankee Operational Quality Assurance-Program (YOQAP-1).
2.2 Enaineering Engineering services will be provided by organizations selected by Vermont Yankee. Piping analysis and related support services will be provided by General Electric Company.
2.3 Installation Contractor The piping installation will be performed by Morrison-Knudsen.
2.4 Support Services 2.4.1 Quality Assurance Each engineer and contractor provides the required quality control and quality assurance services for items within his scope of work.
In addition, Vermont Yankee, via the Yankee Nuclear Services Division, will provide periodic audits of the project's participants to verify compliance with contractors QA/QC plans and procedures.
2.4.2 Health Physics The required health physics controls will be established by Vermont Yankee. Vermont Yankee will be responsible for implementing the health physics program, with assistance from Morrison-Knudsen as required.
2.4.3 Consultants Additional consultants have been retained to provide spe-2 cific expertise or supplement the activities of the pro-ject team personnel.
3.0 ENGINEERING ASPECTS OF PROJECT 3.1 Material Considerations In order to improve the IGSCC resistance of the replacements systems, the orignal Type 304 wrought material will be replaced with controlled chemistry Type 316 seamless pipe and fittings.
The in-drywell components to be replaced are:
1.
Jet pump inlet nozzle safe ends 2.
Recirculation suction nozzlo safe ends 3.
All wrought recirculation system piping and compcnents 4.
Recirculation bypass line 5.
Wrought stainless steel portions of the RHR System.
l All reused components, such as pumps and valves, will be weld clad at the weld interface, if required, to ensure that the HAZ region is protected by material having a ferrite number of SFN minimum.
3.2 Desian Considerations The replacement Recirculation System has been redesigned to reflect advancements in piping system design. ' Specific design improvements' include:
1.
Use of seamless material to eliminate longitudinal welds 2.
Use of integrally forged fittings and bent pipe to reduce welds.
3.
Deletion of ring header end caps to eliminate crud traps.
4.
Deletion of loop crosstie valves to eliminate crud traps.
5.
Improved ID counterbore to facilitate ISI.
6.
Cylindrical prolongation on all fittings to facilitate ISI.
7.
Surface treatrent to minimize future radiation build-up.
A schematic of the new Recirculation System design is shown in Figure 1.
3.3 Fabrication Considerations Tight controls have been imposed on the fabrication process t.)
ensure that the IGSCC resistance of the material is not degraded during fabrication.
Material test coupons subjected to actual fabrication processes will be tested to ensure the required physical and IGSCC resistance pro-perties are achieved.
3.4 Analysis Considerations The replacement piping system will. be reanalyzed in accordance with the rules of ANSI B31.1, which was the original analysis code. The 1977 Edition has been selected to provide consistency with the Vermont Yankee seismic piping upgrade program on piping outside con-tainment.
The' seismic input will'be based on a safe shutdown earthquake anchored at 0.14g, as specified in the original plant design.
However, the ground response will be based upon USNRC Regulatory Guide 1.00, which is more severe than the original design basis.
Other analysis upgrades include 30 versus 2D earthquake and exten-sion of the cutoff frequency to 33 Hz.versus 20 Hz.
Structural damping will be based on USNRC Regulatory Guide 1.61 requirements, except for piping which will utilize PVRC damping as defined by ASME Code Case N-411 and as recommended by NUREG 1061.
3.5 Codes and Standards All material and fabrication requirements for the replacement systems will meet the reequirements.of the ASME Code Section III, 1980 Edition through Summer 1982 Addenda. This requirenent is con-
~sistent with Section XI and exceeds the original construction requirements for Vermont Yankee.
o As stated earlier, the analysis code will be 831.1, 1977 Edition.
The material and fabrication requirements meet or exceed the requirements of 831.1, 1977.
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4.0 FABRICATION AND CONSTRUCTION ASPECTS OF PROJECT 4.1 Weld Joint Design Weldjointdesignswillbeselectedtoprovidejointswithanaccept-able minimum of weld-induced residual stress. All circumferential i
butt-shop welds will be solution annealed to eliminate welding resi-dual stresses. All circumferented butt field welds will be treated with induction heating stress improvement.
4.2 Mock-Ups and Training An extensive mock-up and training program has been conducted. Mock-ups were developed for the following areas:
1.
.3.
Recirculation inlet-safe-end thermal sleeve weld 4.
Bottom head drain replacement All personnel will be trained on mock-ups before performing produc-tion welds.
4.3 NDE Construction NDS will be performed in accordance with the C)nstruc-tion code.
Following construction and before IHSI a baseline examination will be performed in accordance with Section XI.
Following IHSI a sample of welds will be re-inspected to verify that IHSI has not affected the baseline inspection results.
5.0 DESIGN CONTROLS 1
5.1 Engineerino Desian Chance The replacement of the recirculation and RHR piping is being per-formed as an Engineering Design Change Request (EDCR) under the pro-visions.of the Yankee Operational Quality Assurance Program j
. (YOQAP-1).
Engineerin'g specifications have been prepared for the following activities:
l
i 1.
Piping material procurement and fabrication 2.
Safe end material procurement and fabrication 3.
Site installation of replacement piping systems.
4.
Analysis requirements for replacement piping systems 5.
Recirculation loop flow elements 6.
Replacement thermal insulation 5.2 50.59 Review A 50.59 review has been performed and documented as part of the,EDCR package.
It has been determined that the piping system replacement does not constitute an unreviewed safety question as defined by 10CFR50.59.
6.0 ALARA CONSIDERATIONS The ALARA aspects of the project have been reported in a separate report, as required by USNRC Generic Letter 84-07.
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