GNRO-2013/00031, Corrected Response to NRC Request for Additional Information Regarding License Amendment Request for Power Range Neutron Monitoring System

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Corrected Response to NRC Request for Additional Information Regarding License Amendment Request for Power Range Neutron Monitoring System
ML13150A008
Person / Time
Site: Grand Gulf 
Issue date: 05/22/2013
From: Kevin Mulligan
Entergy Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML131500015 List:
References
GNRO-2013/00031, TAC ME2531
Download: ML13150A008 (10)
v • d • e


Text

When Attachment 1 is removed from this letter, the entire document is NON-PROPRIETARY.

contains PROPRIETARY information.

GNRO-2013/00031 May 22, 2013 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

Corrected Response to NRC Request for Additional Information Pertaining to License Amendment Request for Power Range Neutron Monitoring System (TAC No. ME2531)

Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29

REFERENCE:

Entergy Operations, Inc. letter to the NRC (GNRO-2011/00039),

Responses to NRC Requests for Additional Information Pertaining to License Amendment Request for Power Range Neutron Monitoring System (TAC No. ME2531), May 26, 2011

Dear Sir or Madam:

In the referenced letter, Entergy Operations, Inc. (Entergy) submitted to the NRC responses to Requests for Additional Information (RAIs) pertaining to a license amendment request (LAR), which proposed to revise the Grand Gulf Nuclear Station (GGNS) Technical Specifications (TS) to reflect the installation of the digital General Electric-Hitachi (GEH)

Nuclear Measurement Analysis and Control (NUMAC) Power Range Neutron Monitoring System (PRNMS). Included in this submittal was a response to RAI 18, which asked for a description of testing performed to ensure PRNMS safety functions met the requirements of NRC Staff Positions 1.19 and 1.20 of NRC Digital Instrumentation and Control Interim Staff Guidance DI&C-ISG-04, Highly-Integrated Control Rooms Communications Issues (HICRc).

On April 9, 2013, General Electric - Hitachi (GEH) informed Entergy via letter they had identified errors in the response to RAI 18. Entergy has reviewed the errors and has determined that the original conclusion, that Staff Positions 1.19 and 1.20 are met, is not affected and remains valid. Entergy has discussed these errors with GGNS NRC project manager.

As requested by the NRC project manager, Entergy is providing in Attachment 1 a corrected response to RAI 18. GEH considers certain information contained in the attachment to be proprietary and, therefore, requests they be withheld from public disclosure in accordance Entergy Operations, Inc.

P. O. Box 756 Port Gibson, MS 39150 Kevin J. Mulligan Site Vice President Grand Gulf Nuclear Station Tel. (601) 437-6409

ATTACHMENT 2 GRAND GULF NUCLEAR STATION GNRO-2013/00031 CORRECTED RESPONSE TO NRC RAI 18 (NON-PROPRIETARY VERSION) to GNRO-2013/00031 Page 1 of 6 NON-PROPRIETARY INFORMATION CORRECTED RESPONSE TO NRC RAI 18 NRC RAI 18 Staff Positions 1.19 and 1.20 of DI&C-ISG-04 address the potential impact of data throughput and data error rates on worst-case response time.

Describe in detail the testing performed to ensure proper performance of all safety functions to satisfy the above criteria or to determine the proposed approach is an acceptable alternative.

The following further clarifies the rationale for this RAI but does not include additional information requests. The RAI response DI&C-ISG-04 compliance matrix in Attachment 3 to GNRO-2010/00040, items 64 and 65, did not address throughput and error rates observed through design and qualification testing on system response time calculations.

Response

Supporting Information:

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Staff Position 1.19:

If data rates exceed the capacity of a communications link or the ability of nodes to handle traffic, the system will suffer congestion. All links and nodes should have sufficient capacity to support all functions. The applicant should identify the true data rate, including overhead, to ensure that communication bandwidth is sufficient to ensure proper performance of all safety functions. Communications throughput thresholds and safety system sensitivity to communications throughput issues should be confirmed by testing.

The following response explains how PRNMS satisfies the criteria of Staff Position 1.19. This response:

Discusses the features used to ensure sufficient link capacity, Identifies link capacity, and Details testing performed to ensure communication links have sufficient capacity to ensure proper performance of safety functions.

to GNRO-2013/00031 Page 2 of 6 NON-PROPRIETARY INFORMATION

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to GNRO-2013/00031 Page 3 of 6 NON-PROPRIETARY INFORMATION Table 18-1 FDDI Link Capacity Usage

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to GNRO-2013/00031 Page 4 of 6 NON-PROPRIETARY INFORMATION

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Based on the above information, the PRNMS system communication link features, capacity usage information, and testing described in the response satisfy the criteria of Staff Position 1.19.

Staff Position 1.20:

The safety system response time calculations should assume a data error rate that is greater than or equal to the design basis error rate and is supported by the error rate observed in design and qualification testing.

The following response explains how PRNMS satisfies the criteria of Staff Position 1.20.

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to GNRO-2013/00031 Page 5 of 6 NON-PROPRIETARY INFORMATION Table 18-2 Data Error Rate Impact to PRNM System Response Time

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Table 18-3 Maximum Expected PRNMS Response Time

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to GNRO-2013/00031 Page 6 of 6 NON-PROPRIETARY INFORMATION The data error rate for each safety-related communication link was established and used to determine the impact of data errors on safety system response time. The established data error rates are supported by testing during the development of PRNMS. Therefore, the criteria of Staff Position 1.20 are met.

ATTACHMENT 3 GRAND GULF NUCLEAR STATION GNRO-2013/00031 GEH AFFIDAVIT SUPPORTING PROPRIETARY INFORMATION PROVIDED IN ATTACHMENT 1

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