ML070600291

From kanterella
Jump to navigation Jump to search
Handouts to LaSalle, Units 1 and 2 - Summary of January 26, 2007, Pre-Application Meeting with Exelon, for Ganged Rod Withdrawal and Ultimate Heat Sink Amendment Denial
ML070600291
Person / Time
Site: LaSalle  Constellation icon.png
Issue date: 03/12/2007
From:
Exelon Nuclear
To:
Office of Nuclear Reactor Regulation
Sands S,NRR/DORL, 415-3154
Shared Package
ML070650255 List:
References
Download: ML070600291 (26)
v • d • e


Text

Nuclear LaSalle County Station Pre-Application Meeting License Amendment Request Ganged Rod Drive Capability Enclosure 2

Introduction ExelIn Nuclear Objective of Meetinq

> Review the technical and regulatory aspects of a planned License Amendment Request (LAR) for Ganged Rod Drive Capability at LaSalle County Station (LSCS).

> Review an outline of a draft LAR with respect to the required scope and level of detail.

> Confirm that current LAR outline, including any identified enhancements, satisfy required scope.

> Discuss the Regulatory Finding that would be necessary for LAR approval.

2

Introduction Exeuleanr Nuclea-r Topics and Presenters

>Review of Issue - Terry Simpkin, Regulatory Assurance Manager, LSCS Review of LAR Outline - Darin Benyak, Licensing and Regulatory Affairs SProposed Regulatory Finding - Darin Benyak SCurrent Project Status - Bob Fredricksen, Lead Design Engineer, LSCS 3

Issue Review Exel' [flsm Nuclear Rod Control Management System EGC is replacing the current LSCS Reactor Manual Control System (RMCS) with a new design called the Rod Control Management System (RCMS).

The current RMCS uses discrete digital electronics and dynamic logic to control rod motion. The replacement RCMS will be a digital microprocessor-based system.

The RCMS will retain all of the system-level functions of the existing RMCS and Rod Worth Minimizer (RWM), as well as add additional capabilities.

The replacement system is classified as non-safety-related, and has been designed to the same regulatory criteria and standards as the existing system, 4

Issue Review Nuclear Added Functionality of RCMS

> Enhanced implementation and documentation of control rod maintenance and surveillance activities.

> Improved control rod movement operations that are required for control rod drive functionality.

> Enhanced the confirmation of reactor shutdown following a scram.

Added the capability to move multiple rods (up to four) in a single gang (i.e., Ganged Rod Drive Capability).

The RCMS is being installed in accordance with the requirements of 10 CFR 50.59, with the exception of Ganged Rod Drive Capability.

5

Issue Review IS.

Nuclear Operational and Safety Benefits With Ganged Rod Drive Capability, the RCMS will:

Reduce operational challenges by reducing the amount of time that the reactor is in the Intermediate and Startup range power levels during startups. These power levels require a heightened level of reactivity management attention and resources.

Enhance SCRAM avoidance by allowing the rapid insertion of CRAM rods (rods specified in analyzed sequences for the purpose of significantly reducing reactor power rapidly) during plant transients.

6

Issue Review ExelIn Nuclear Ganged Rod Drive Capability

- Low Power," does not address or consider simultaneous movement of multiple rods.

> EGC proposes to revise the LSCS Licensing Basis to include, in the UFSAR, the description of a potential multiple rod withdrawal error at low power event as an "infrequent incident," similar to the description of a potential single rod withdrawal error event (i.e., UFSAR Section 15.4.1.2, "Continuous Rod Withdrawal Error").

7

Issue Review Exekons.

Nuclear September 19, 2006 Pre-Application Meeting

> Objective was to identify the specific scope and level of detail of information needed to complete a review of an LAR for Ganged Rod Drive Capability at LSCS.

SMeeting Summary was issued on November 28, 2006 with nine specific information requirements.

8

Issue Review Nuclear September 19, 2006 Meeting: LAR Information Requirements

1. Describe intent of LAR
2. Describe internal and external communication interfaces
3. Describe hardware and software controls that restrict rod movement
4. Describe cyber security
5. Describe component qualification
6. Address Regulatory Guide 1.97 and Emergency Operating Procedure applicability
7. Describe the processing of Rod Block signals
8. Provide a Failure Analysis (three sub-items)
a. Analysis of Single Failures and submittal of Failure Modes and Effects Analysis
b. Characterization of likelihood of common-mode software failure, including description of software development and testing
c. Description of the consequences if the low probability event were to occur (i.e., failures leading to uncontrolled withdrawal of rod gang)
9. Address all NUREG-0800 accidents involving rod movement in No Significant Hazards Consideration 9

Draft LAR Outline :xe l ,.

Nuclear General LAR Outline; Detailed Outline Provided as Attachment Description SIntent of LAR (Item 1)

Proposed Change SRevision of Licensing Basis (Item 1)

Technical Evaluation SDescription and Design Basis (Items 2, 3, 4, 5, 6, and 7)

> Failure Analysis (Items 8a, 8b, and 8c)

Regulatory Analysis SNo Significant Hazards Consideration (item 9)

Appendices SNetwork Diagram (Item 4)

SRCMS Failure Modes and Effects Analysis (Item 8a) 10

ProposedRegulatory Finding Exel(n+/-f Nuclear "The requirements of General Design Criteria (GDC) 10, 17, 20, 24, and 25 had been met for ganged rod drive capabilityat LaSalle County Station as part of the Rod Control Management System, since the system design contains a Rod Worth Minimizer.

This system has been reviewed and found acceptable because single failures in the reactorcontrol system, which could result in uncontrolled withdrawal of control rods under low-power conditions, have been precluded.

The scope of this review has included the design features which act to prevent such withdrawals."

11

CurrentProject Status Exelon.

Nuclear SDesign Specifications Complete SHardware Build Complete

~ Software Code Written; Code tested SIntegration Testing in progress SV&V and Factory Acceptance Testing will be completed in July SParallel unit on-site for Exelon evaluation SInfrastructure installation in-progress 12

Attachment Exelor,'

Nuclear LaSalle County Station Draft License Amendment Request Ganged Rod Withdrawal Detailed Outline.

13

Exeln' fln Nuclear LaSalle County Station Ultimate Heat Sink Regulatory Resolution and Optimum Approach for Submittal of License Amendment Request

Introduction Exelri5 .

Nucdea.r Obiective of Meeting

> Review the 2006 License Amendment Request (LAR) for Ultimate Heat Sink (UHS) at LaSalle County Station

> Review of the NRC Safety Evaluation

> Discussion of the NRC approved LaSalle County Station UHS Licensing Basis and Plant Design

> Exelon's Perspective of the License Amendment Denial

> Regulatory Resolution Pathways 15

Introduction Exelorts Nuclear Topics and Presenters

>Review of the original LAR Alison Mackellar, Corporate Licensing Engineer SDiscussion of Licensing Basis and Design Terry Simpkin, Regulatory Assurance. Manager LaSalle

> Review of Denial SE Alison Mackellar, Corporate Licensing Engineer

> Exelon's Perspective on the Denial Darin Benyak, Corporate Licensing Manager

> Regulatory Resolution Pathways Darin Benyak, Corporate Licensing Manager 16

Original LAR Exelen .

Nuclear UHS License Amendment Request The original LAR proposed a change to increase the Technical Specification (TS) indicated temperature limit of UHS from < 100°F to < 101.5 0F The increase was to be achieved by reducing the measurement uncertainty by replacing existing thermocouples with higher precision temperature measuring equipment (i.e., RTDs)

The Circulating Water (CW) temperature instrumentation indication loop(s) are of an equivalent design The method and procedures used to determine UHS are unchanged 17

LAR Original LAR Exelkn,.

Original Nucdea.r CW Inlet Temperature Trend Data from Plant Process Computer UNIT 1 I MoDEo,i fir1I 2 Trend . 1/24/2007 I I ACTIVE A n Ii 2 trendJ 13:45:05 I1

"~~ - tr n I . .. ... I, ,

Start Time: MM Mt 1 Archive Sample Rate:

End Time:

  • M* *M*a*M Real-Time Sample Rate:

51.99 DnGF X T63~0 52.80 52.80 52.12 DEGF [

52.60 52.60 62.40 . 24.20..

. 13:20:001.24.20..13:30.001/.4/200... . 13:400....

52.40 52.20 52.20 52.00 52.00 51.80 51.80 51.60 51.60 51.40 51.40 51.20 51.20 u,1[pI U"

1/24/2007 13:20:00 1/24/200713:30:00 1/24/2007 13:40:00

OriginalLAR Exelon,.

Simplified Circulating Water (CW) System Nuclear 19

Original LAR Exelek n Nuclear UHS LAR Technical Basis The UHS post-accident temperature maximum allowable cooling water inlet value = 1041F Existing Analysis

> 1041F = 100°F (TS max) + 20 F (transient) +/- 1.80 F (calculated thermocouple uncertainty) + .20 F (margin added)

Analysis Results Remains Unchanged

> 104'F = 101.5 0 F (new TS max) + 20 F (transient) +/- 0.31°F (calculated RTD uncertainty) + 0.19 0 F (margin added) 20

UHS Design Exelk ns.

Nuclear UHS Licensing Basis and Plant Design SR 3.7.3.1 was added to LaSalle TS during ITS in 2001 The CW temperature instrumentation indication loop(s) originally designed as non-safety-related The replacement instrumentation used to measure the UHS temperature is non-safety-related NES-EIC-20.04 - methodology reviewed during ITS Calculation performed in accordance with NEC-EIC-20.04 and was appropriate -for instrument uncertainty for non-safety related indicating loops The method and procedures used to determine UHS are unchanged 21

NRC SE Review Exelon.

Nuclear Review of the NRC Safety Evaluation (SE)

"the degree of measurement accuracy that would be required to support the requested modification is not adequately demonstrated in Exelon's analysis" "the TS modification itself does not adequately address single-unit operation (if only one unit is operating the lack of flow to the other unit could cause the temperature measurements associated with that unit to become non-representative of the UHS temperature.)"

22

NRC SE Review ExelNule.

Nucea-r Review of the NRC Safety Evaluation.(SE)

"the degree of measurement accuracy that would be required to support the requested modification is not adequately demonstrated in Exelon's analysis"

> RG 1.105 -graded approach

> HICB-12 SISA-$67.04

> NES-EIC-20.04 - reviewed with ITS SHICB issued TIA on UHS instrument accuracy for Millstone 2 SWaterford Unit 3 23

NRC SE Review Exekn~.

Nuclear Review of the NRC Safety Evaluation (SE)

> TS modification itself does not adequately address single-unit "the operation (if only one unit is operating the lack of flow to the other unit could cause the temperature measurements associated with that unit to become non-representative of the UHS temperature)"

> The Circulating Water (CW) temperature instrumentation indication loop(s) are of an equivalent design

> The replacement instrumentation used to measure the UHS temperature is non-safety-related, installed and fully functional SThe method and procedures used to determine UHS are unchanged

> The CW temperature of the installed RTDs on either unit is representative of the UHS temperature with a CW pump running

> Ifthe unit does not have a CW pump in operation, the surveillance procedure directs the CW temperature to be recorded from a unit that does have a CW pump in operation 24

Discussion ExelN flear Nudea.r Exelon Perspective of Denial Change in NRC position on measurement uncertainty methodology for non-safety related systems

> Challenging current design and licensing basis for LaSalle CW system 25

Discussion Exeulear~

Nuclear SRe-gulatory Resolution Pathways Identify additional issues with Exelon approach

> Resolve Issues

> Resubmittal 26

Retrieved from "https://kanterella.com/w/index.php?title=ML070600291&oldid=2251814"