ML103500204

Request for Additional Information, Regarding Request for Exemption

ML103500204
Person / Time
Site:	Indian Point
Issue date:	12/16/2010
From:	Boska J Plant Licensing Branch 1
To:	Entergy Nuclear Operations
Boska J, NRR, 301-415-2901
References
tac me0798, TAC ME0799
Download: ML103500204 (7)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 December 16, 2010 Vice President, Operations Entergy Nuclear Operations, Inc.

Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 Buchanan, NY 10511-0249 SUB.JECT:

INDIAN POINT NUCLEAR GENERATING UNIT NOS. 2 AND 3 - REQUEST FOR ADDITIONAL INFORMATION REGARDING REQUEST FOR EXEMPTION (TAC NOS. ME0798 AND ME0799)

Dear Sir or Madam:

By two letters dated March 6, 2009, and two letters dated October 1, 2009, Entergy Nuclear Operations, Inc. (Entergy) submitted to the Nuclear Regulatory Commission (NRC) requests for exemptions from Title 10 of the Code of Federal Regulations, Part 50, Appendix R, "Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979," Paragraph III.G.2, for Indian Point Nuclear Generating Unit Nos. 2 and 3. The letters are available in the NRC's Agencywide Documents Access and Management System (ADAMS), Accession Nos.

ML090770151, ML090760993, ML092810230, and ML092810231. The request was made to allow the use of operator manual actions in lieu of meeting the separation requirements contained in Paragraph III.G.2.

By letter dated January 20, 2010, ADAMS Accession No. ML100150128, the NRC staff requested additional information. Entergy submitted a response in two letters dated May 4, 2010, ADAMS Accession Nos. ML101320230 and ML101320263. By letter dated August 11, 2010, ADAMS Accession No. ML102180331, the NRC staff requested additional information.

Entergy submitted a response in two letters dated September 29, 2010, ADAMS Accession Nos.

ML102930234 and ML102930237. The NRC staff is reviewing the responses and has determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information (RAI). The NRC staff has discussed with Entergy staff that a response to the RAI is needed within 30 days of the date of this letter.

- 2 Please contact me at (301) 415-2901 if you have any questions on this issue.

Sincerely, J hn P. Boska, Senior Project Manager lant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-247 and 50-286

Enclosure:

RAI cc w/encl: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION (RAI)

REGARDING APPENDIX R EXEMPTION REQUEST ENTERGY NUCLEAR OPERATIONS, INC.

INDIAN POINT NUCLEAR GENERATING UNIT NOS. 2 AND 3 DOCKET NOS. 50-247 AND 50-286 By two letters dated March 6, 2009, and two letters dated October 1, 2009, Entergy Nuclear Operations, Inc. (Entergy) submitted to the Nuclear Regulatory Commission (NRC) requests for exemptions from Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Appendix R, "Fire Protection Program for Nuclear Power Facilities Operating Prior to January 1, 1979,"

Paragraph III.G.2, for Indian Point Nuclear Generating Unit Nos. 2 and 3 (IP2 and IP3). The letters are available in the NRC's Agencywide Documents Access and Management System (ADAMS), Accession Nos. ML090770151, ML090760993, ML092810230, and ML092810231.

The request was made to allow the use of operator manual actions (OMAs) in lieu of meeting the separation requirements contained in Paragraph III.G.2.

By letter dated January 20, 2010, ADAMS Accession No. ML100150128, the NRC staff requested additional information. Entergy submitted a response in two letters dated May 4, 2010, ADAMS Accession Nos. ML101320230 and ML101320263. By letter dated August 11, 2010, ADAMS Accession No. ML102180331, the NRC staff requested additional information.

Entergy submitted a response in two letters dated September 29, 2010, ADAMS Accession Nos.

ML102930234 and ML102930237. The NRC staff is reviewing the responses and has the following questions:

Questions Related to IP2 OMAs Relied On To Restore Operation of Reactor Coolant System Makeup Capability RAI-01.1 The September 29, 2010, response states that an intra-cable (conductor-to-conductor) fault within cable CK1-.JB5/1 would cause the volume control tank (VCT) outlet valve (LCV-113C) to spuriously close. If this failure were to occur at a time when the credited charging pump (21 Charging Pump) is in operation, or if the fire damage to unspecified control cables caused the 21 pump to spuriously start, the credited charging pump would suffer prompt damage due to a loss of suction.

The results of recent cable fire tests conducted by both the NRC and industry show that given cable damage, the occurrence of the type of fault required to cause LCV-112C to close (i.e., an intra-cable fault) is highly likely. Thus, the potential for a spurious closure of LCV-112C with a concurrent spurious start of the charging pump cannot be ignored. However, the September 29, 2010, response does not provide sufficient information to determine the likelihood of fire-induced failures that would be necessary to cause this event. For example, since the response does not provide any information related to the charging pump control cables, a spurious pump start is assumed to occur. In the absence of any discussion of the mitigating circumstances available to Enclosure

- 2 reduce the likelihood of this event, it is assumed that LCV-112C closes and the pump is promptly damaged.

As another example, the September 29, 2010, response indicates that in addition to a loss of offsite power (which is assumed in the analysis), a fire in Fire Area J could cause a loss of 480 volt power supplied from the emergency diesel generator (EDG) via buses 5 and 6. The response identifies the cables of concern; however, it does not describe the specific number or types of cable faults that are required to cause this event. In addition, the response does not identify the shutdown equipment supplied from buses 5 and 6 or the impact a loss of power to this equipment would have on the ability to achieve and maintain hot shutdown. In addition, although certain cables of concern lack separation from potential ignition sources, the response does not provide any justification why this configuration, when considered in conjunction with other fire safety features, provides an appropriate level of defense-in-depth to minimize the need for implementing the requested OMAs. For example, a high-energy arcing fault (HEAF) emanating from switchgear located in Fire Zone 43 could cause prompt damage to cables of concern which are routed in close proximity to it. However, in lieu of describing the likelihood or impact of this scenario, the response (Table RAI-06.1-1 Page 28) credits prompt detection of fire by plant personnel. Given the nature of HEAF events and the close proximity of required cables to the switchgear, reliance on plant personnel may not provide an appropriate level of defense in depth.

Therefore, for cases such as the examples cited above, the request should provide a detailed discussion of the plant-specific features which would minimize the likelihood of occurrence.

Such features may include, for example, a combination of features such as: detection, suppression, separation distance between cables of concern, separation of cables from potential sources of ignition and HEAF, the type of raceway (conduit, cable tray), cable type and number and type of circuit faults required to cause the undesired event.

Where a requested OMA is being credited to mitigate the impact of fire-induced failures of required shutdown equipment, additional information is needed to assess the likelihood of a fire to create the need for the requested OMAs. For each of the requested OMAs, ensure that information has been provided to demonstrate how the underlying purpose of the rule (10 CFR 50 Appendix R) is met. For example, identify:

1.

all cables that could cause components of concern to spuriously start, stop, change position, become damaged or otherwise fail in an undesired manner for hot shutdown.

2.

the routing of these cables within each of the fire areas identified in the request,

3.

the proximity of the identified cables of concern to each other (in feet and inches),

4.

the type of cable faults required to cause the component(s) to fail in an undesired manner for post-fire safe shutdown,

5.

the spatial relationship of each cable to potential ignition sources and/or high energy arcing faults, and

6.

any other plant specific features that serve to minimize the likelihood of the undesired event.

RAI-01.2 The September 29, 2010, response indicates that LCV-112C could fail open as a result of fire damage. With continued operation of the charging pump in this scenario, draindown of the VCT

- 3 could occur resulting in the introduction of hydrogen into the pump suction, damaging the pump.

However, it is not clear if potential impact of this failure mode has been fully assessed in the request. Provide information which clearly demonstrates that LCV-112C failing in the open position has been fully evaluated for its impact on the ability to achieve and maintain hot shutdown. For fire areas where LCV-112C is found to be vulnerable to this failure mode, the response should also include information requested in the RAI above.

RAI-01.3 Several inconsistencies were noted in the September 29, 2010, response regarding the capability of operator actions to prevent pump damage by proactively shutting down the required/credited charging pump. Specific examples include:

1.

Response to RAI 01.1 Item 1 (page 2) which states: If, the required/credited charging pump has been shut down proactively, no damage to the pump will occur.

2.

Response to RAI 01.1 Item 5 (page 8) which states, in part: The pump is secured by placing the control room control switch in OFF and pullout. This action will stop 21 Charging Pump, to protect against any damage that could be caused by a spontaneous loss of all suction paths. Despite placing 21 Charging Pump in OFF/pullout,... an internal conductor-to-conductor fault on the 21 Charging Pump control cable(s) could result in a spurious start of 21 Charging Pump.

3.

Response to RAI 07.1, which states, in part: This potential failure mode is mitigated by procedural guidance to secure the charging pump in the event of a confirmed fire condition and to start another charging pump to support continued operation until the proper response to the fire condition is assessed. In this way, the charging pump will be protected from any damage scenario that may be caused by spurious loss of pump suction sources.

In summary, although the responses provided for RAJ 01.1 (Item 1) and RAI 07.1 indicate that the control room action will preclude damage to the charging pump, the response to RAI 01.1 (Item 5) indicates that pump damage may still occur. Provide further clarification of the capability of this action to preclude pump damage. Where this action is credited, provide a detailed discussion of any plant-specific features which serve to minimize the likelihood of fire damage to all cables of concern.

RAI-01.4 The September 29, 2010, response indicates that Cable YZ1-~IB5, provides the interlock between the refueling water storage tank (RWST) outlet valve LCV-112B and (under normal operating conditions) an inter-cable (cable to cable) Hot Short would be required to cause LCV 112C to spuriously close. However, the response does not clearly identify circuit faults that would be required to prevent normally-closed RWST outlet valve LCV-112B from opening automatically as designed in response to a close signal from LCV-112C. Identify the cables of concern, and describe their routing, type of cable faults (Open, Short to ground, inter-cable hot short or intra-cable hot short) required to prevent the normally-closed RWST outlet valve LCV 112B from automatically opening, and the proximity to other cables that, in conjunction with fire damage to this cable(s) could result in a loss of all charging suction (e.g. LCV-112C control cables).

-4 Questions Related to IP3 The RAI questions above also apply to IP3, which has plant systems which are similar to IP2.

Please provide answers specific to IP3, with the equipment designators changed to show the IP3 equipment.

- 2 Please contact me at (301) 415-2901 if you have any questions on this issue.

Sincerely, IRAI John P. Boska, Senior Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-247 and 50-286

Enclosure:

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