NL-11-0298, Comment (4) of M. J. Ajuni on Behalf of Southern Nuclear Operating Co. Draft NRC Regulatory Issue Summary (RIS) 2011-XX, Adequacy of Station Electric Distribution System Voltages
| ML110540360 | |
| Person / Time | |
|---|---|
| Site: | Hatch, Vogtle, Farley, 05000026 |
| Issue date: | 02/17/2011 |
| From: | Ajuni M Southern Nuclear Operating Co |
| To: | Rulemaking, Directives, and Editing Branch, Document Control Desk |
| References | |
| NL-11-0298, NRC-2011-0013 | |
| Download: ML110540360 (7) | |
Text
iUE; .- 7 7 TiVES Mark J. Ajiluni, P.E. Southern Nuclear Nuclear Licensing Director Operating Company, Inc.
40 Inverness Center Parkway Post Office Box 1295 Birmingham, Alabama 35201 February 17, 2011 Tel 205.992.7673 I '~F I'-J Fi1, 2: q8 Fax 205.992.7885 Docket Nos.: 50-321 50-348 50-424 SQJUTHFRN 50-366 50-364 50-026 R"'I\- ;\D COMPANY NL-1 1-0298 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Joseph M. Farley Nuclear Plant Edwin I. Hatch Nuclear Plant Vogtle Electric Generating Plant Comments on Draft NRC Regulatory Issue Summary 201 1-XX, "Adequacy of Station Electric Distribution System Voltages" Docket ID NRC-2011-0013 Ladies and Gentlemen:
In a January 18, 2011 Federal Register Notice (76FR 2924) the Nuclear Regulatory Commission (NRC) requested public comments on a Draft NRC Regulatory Issue Summary (RIS) 201 1-XX, "Adequacy of Station Electric Distribution System Voltages".
This letter is to advise that Southern Nuclear Operating Company (SNC) endorses the comments submitted by NEI. SNC comments are provided in Enclosure 1.
Respectfully submitted,
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Sincerely, IThAA ýOL-Cf M. J. Ajluni Nuclear Licensing Director MJAIGAL/lac
Enclosures:
- 1. Comments on Draft NRC Regulatory Issue Summary 2011 -XX "Adequacy of Station Electric Distribution System Voltages" Docket ID NRC-2011-0013
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U. S. Nuclear Regulatory Commission NL-1 1-0298 Page 2 cc: Southern Nuclear Operating Company Mr. J. T. Gasser, Executive Vice President Mr. L. M. Stinson, Vice President Fleet Operations Support- Farley Mr. D. R. Madison, Vice President - Hatch Mr. T. E. Tynan, Vice President - Vogtle Ms. P. M. Marino, Vice President - Engineering RType: CGA02.001 U. S. Nuclear Regulatory Commission Mr. L. A. Reyes, Regional Administrator Mr. R. E. Martin, NRR Project Manager - Farley, Hatch and Vogtle Mr. E. L. Crowe, Senior Resident Inspector - Farley Mr. E. D. Morris, Senior Resident Inspector - Hatch Mr. M. Cain, Senior Resident Inspector - Vogtle Mr. P. G. Boyle, NRR Project Manager
Joseph M. Farley Nuclear Plant Edwin I. Hatch Nuclear Plant Vogtle Electric Generating Plant Comments on Draft NRC Regulatory Issue Summary 2011-XX "Adequacy of Station Electric Distribution System Voltages" Docket ID NRC-2011-0013 Enclosure 1 Comments on Draft NRC Regulatory Issue Summary 201 1-XX, "Adequacy of Station Electric Distribution System Voltages" Docket ID NRC-2011-0013
Comments on Draft NRC Regulatory Issue Summary 2011 -XX, "Adequacy of Station Electric Distribution System Voltages" Docket ID NRC-2011-0013 ID Section, Page, Line Comment Proposed Resolution Number 1 General Include a definition of key terms (ex. Normal grid operation, sustained degraded voltage) 2 General The RIS does not address completely the specific requirements Include missing positions especially those in the PSB-1 (ADAMS Accession No. ML052350520), related to determining minimum expected Arkansas Nuclear One (ADAMS Accession offsite system voltages and testing.
No.ML0311801180), and Millstone (ADAMS Accession No. ML093521388) documents. In some cases specific positions in the above documents were omitted from the RIS.
3 General The RIS lacks adequate guidance to perform the requested Provide a guideline with examples on how calculation(s) without additional interpretations by the licensee to perform the calculation(s) including and auditors as to the intent of the provided guidance. expected assumptions, other considerations, and criteria to be used for acceptance.
E1-1
Comments on Draft NRC Regulatory Issue Summary 201 1-XX, "Adequacy of Station Electric Distribution System Voltages" Docket ID NRC-2011-0013 ID Section, Page, Line Comment Proposed Resolution Number 4 General The RIS provides some examples of plants that have NRC reviewed and approved analyses and goes on to point out that "backfit rule" was applied because the staff believed the sites were not in compliance with regulations even though they had approved the analysis. How is a licensee who has an NRC approved or acceptable analysis supposed to know that their analysis is no longer acceptable? The RIS needs more clarification with regard to individual plant licensing bases if it is to be useful to licenses.
Some plants have installed degraded grid alarm systems and, at the staff request, included them in Unit Operating Technical Specifications. Required operator actions related to degraded grid conditions are specified in the bases and procedures. The RIS does not discuss this approach.
There are a number of plants that have URIs related to this issue. Issuance of this RIS could be used by inspectors to close the URIs to violations without regard to plant specific licensing bases, resulting in regulation by inspection..
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Comments on Draft NRC Regulatory Issue Summary 2011 -XX, "Adequacy of Station Electric Distribution System Voltages" Docket ID NRC-2011-0013 ID Section, Page, Line Comment Proposed Resolution Number 5 Ref."Summary of Issues", The RIS states "The Class 1E buses should separate from the Remove or clarify this statement since pg. 6, Item 1. "Degraded offsite power system within a few seconds ifan accident occurs proper offsite system design and Voltage Relaying Design coincident with sustained degraded voltage conditions." operation renders such simultaneous Calculations", Line 5. postulated events as incredible.
GDC 17 describes the requirements for onsite and offsite power systems. One of its requirements is that they each provide sufficient capacity and capability to mitigate postulated events. The events are described in Chapter 15 "Accident Analysis". These analyses assume Loss of Offsite Power simultaneous with the event. They do not require assuming degraded grid voltage condition prior to an event occurring. In addition because of FERC and NERC requirements for voltage control, the likelihood of a chapter 15 accident occurring concurrent with a serious degraded grid voltage condition is not believed to be credible.
6 Ref."Summary of Issues", The RIS states "During normal plant operation, the Class 1E Transmission Operators should be pg. 6, Item 1. "Degraded safety related buses should automatically separate from the allowed time to correct the degraded Voltage Relaying Design power supply within a short interval (typically less than 60 voltage condition while Plant Operators Calculations", Line 7. seconds) ifsustained degraded voltage conditions are monitor the safety bus voltages for detected." adequate voltage.
During normal plant operation (i.e. non LOCA), the degraded grid relay settings may be overly conservative. Therefore automatic separation from the preferred power supply may not be desired.
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Comments on Draft NRC Regulatory Issue Summary 2011-XX, "Adequacy of Station Electric Distribution System Voltages" Docket ID NRC-2011-0013 ID Section, Page, Line Comment Proposed Resolution Number 7 Summary of Issues, DVR The RIS states "in this manner, the DVR ensures adequate This statement needs to be clarified to Setting Design operational (starting and running) voltage to all safety related allow reasonable assumptions for the Calculations, pg. 6 - 7, equipment, independent of voltage controlling equipment status of equipment external to the Class Beginning at the bottom external to the plant safety related electrical distribution system. 1E distribution system. For example it is of page 6. For the purposes of this calculation, no credit should be taken unclear how to perform motor starting for voltage controlling equipment external to the Class 1E calculations without taking credit for some distribution system such as automatic load tap changers and Non 1E voltage controlling equipment.
capacitor banks." Additionally, normal Transmission grid switching to prepare for the next This statement needs to be clarified, contingency to maintain minimum expected transmission system voltages should be allowed.
8 Ref. Summary of Issues, The discussion on time delays does not provide adequate Clarify.
Last paragraph of "DVR criteria for time delay selections.
Setting Design Calculations", pg. 7.
9 Summary of Issues, After paragraph (f)the RIS leaves out the guidance in GL 79-36 Add item 6 of enclosure 2 in GL 79-36 to Guidelines for voltage concerning minimum expected values (item 6 of enclosure 2) the RIS.
drop calculations, item (f) was omitted from the RIS guidance.
pg. 8 E1-4