**NRC INSPECTION MANUAL** SBPB

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TEMPORARY INSTRUCTION 2515/174

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HYDROGEN IGNITER BACKUP POWER VERIFICATION

CORNERSTONE: BARRIER INTEGRITY

APPLICABILITY: This temporary instruction (TI) applies to all holders of
operating licenses for pressurized-water reactors (PWRs) with
ice-condenser containments or boiling-water reactors (BWRs) with Mark
III containments.

2515/174-01 OBJECTIVE

The objective of this TI is to verify that licensees have adequately
implemented commitments related to provision of backup power to
containment hydrogen igniters.

2515/174-02 APPLICABILITY

This TI will be performed at each affected site after completion of
actions to make a backup power supply available to the hydrogen
igniters. At dual-unit sites, the inspection of physical modifications
should only be performed for one unit.

2515/174-03 BACKGROUND

The staff evaluated the potential for early failure of containment
during very low probability events involving damage to the reactor core
in NUREG/CR-6427, "Assessment of the Direct Containment Heat (DCH) Issue
for Plants with Ice Condenser Containments.\" In that report, the
investigators showed that the early containment failure probability of
ice condenser containments is dominated by hydrogen combustion following
core damage events. The staff extended the issue to include BWRs with
Mark III containments because their relatively low free volume and
strength are comparable to PWR ice condenser containments. To further
investigate this issue, the staff opened a generic safety issue, GI-189,
"Susceptibility of Ice Condenser and Mark III Containments to Early
Failure from Hydrogen Combustion during a Severe Accident."

Following a severe core damage event associated with station blackout
(SBO) or other event affecting AC power distribution, the PWR ice
condenser containment and BWR Mark III containment designs have the
potential to fail as a result of large hydrogen detonations. These types
of severe core damage events have a very low probability of occurrence,
but they may produce large quantities of hydrogen through a reaction
between hot metal fuel cladding and steam. Plants with these containment
designs use hydrogen igniters to control the buildup of hydrogen. The
existing hydrogen igniters rely on the plant AC power distribution
system for power, and AC power may not be available for certain events
with the potential to result in severe core damage. A detonation of a
large buildup of hydrogen has the potential to fail these containment
types because of their low design pressure and low free internal volume.
Therefore, for the hydrogen igniters to be effective in preserving
containment integrity, the igniters must have power before a buildup of
hydrogen has developed (i.e., before severe core damage has occurred).

To resolve GI-189, the staff recommended the addition of a backup power
supply for the hydrogen igniters for the plants with ice condenser or
Mark III containments. The staff completed a regulatory analysis
(Reference 1) that indicated that the backup power modification may
provide a substantial safety benefit at a justifiable cost for the PWRs
with ice-condenser containments and voluntary measures proposed by the
licensees for these facilities provided the majority of the benefit. For
the BWRs, none of the options provided a substantial increase in the
overall protection of public health and safety. However, external events
and security insights were not fully evaluated in the regulatory
analysis, and defense-in-depth considerations in improving the balance
among accident prevention and mitigation provide an additional
un-quantified benefit for both containment types. After further
evaluation of security insights, the licensees for the affected plants
committed to provide backup power to the hydrogen igniters that address
the safety issues identified in GI-189 and provide benefit for some
security scenarios. The affected plants are the four dual-unit PWR
nuclear stations with ice condenser containments - McGuire, Catawba, DC
Cook, and Sequoyah; a single-unit PWR nuclear station with an ice
condenser containment - Watts Bar; and four single-unit BWR nuclear
plants with Mark III containments - Grand Gulf, River Bend, Clinton, and
Perry.

2515/174-04 INSPECTION REQUIREMENTS

04.01 General

Evaluate how the licensee has modified plant equipment and implemented
training programs and procedures to provide backup power to at least one
complete train of hydrogen igniters. Voluntary commitments to provide
backup power involve permanent modifications to provide power from a
fixed diesel generator to the igniters, development of procedures and
training to provide power to the igniters through a temporary connection
to a portable generator, or a combination of the two approaches.
References 2 through 8 describe the specific commitments. Because
planned modifications and the configurations of the two units at
affected dual unit sites are similar, the inspection of physical
modifications should only be performed for one unit.

The scope of the inspection differs based on the proposed plant changes.
The capability to provide backup power to the igniters for events
involving severe core damage coincident with a station blackout is
beyond the current design basis of affected facilities. Some proposed
modifications involve permanent connections of alternate power supplies
to power one train of hydrogen igniters. These modifications may require
changes to the facility safety analysis report; less extensive
modifications should not require changes to this document.

Consider the following in performance of the inspection:

a\. Catawba, McGuire, and D.C. Cook PWRs

> 1\. Proposed modifications to these facilities enhance the current
> capability to provide power to one or more igniter trains from fixed
> diesel generators through permanent connections. At Catawba and
> McGuire, the proposed modifications would permanently power one train
> of igniters from the safe shutdown facility and its diesel generator.
> At D.C. Cook, the proposed modification installs a method of
> activating at least one train of the hydrogen igniters in each unit
> from an area outside the control room complex.
>
> 2\. The requirements of Title 10 of the Code of Federal Regulations
> (10 CFR) 50.44, "Combustible Gas Control for Nuclear Power Reactors,"
> and Technical Specification requirements continue to apply to the
> modified hydrogen igniter system. Regulatory Guide 1.7, "Control of
> Combustible Gas Concentrations in Containment," Revision 3, provides
> guidance on acceptable means of complying with 10 CFR 50.44. In RG
> 1.7, the staff states that the combustible gas control systems
> installed at the affected facilities and approved by the NRC as of
> October 16, 2003, are acceptable without modification.
>
> 3\. Inspection Procedure 71111, "Reactor Safety - Initiating Events,
> Mitigating Systems, Barrier Integrity," Attachment 71111.17,
> "Permanent Plant Modifications," (Reference 9) provides inspection
> guidance appropriate for review of these modifications and associated
> safety analysis report changes. Assess the continued compliance with
> the requirements of 10 CFR 50.44 and the ability to reliably provide
> power to the igniters consistent with commitments.

b\. Sequoyah and Watts Bar PWRs

> 1\. The changes at these units involve development of procedures and
> training to support connection of an existing large, mobile diesel
> generator to the electrical distribution system in a manner that
> provides power to at least one train of igniters through temporary
> connections.
>
> 2\. Assess the identified location of the temporary connection to
> verify the ability to reliably provide power to the igniters
> consistent with commitments.

c\. Clinton, Grand Gulf, Perry, and River Bend BWRs

> 1\. The changes at these units involve procurement of a small,
> portable generator and development of procedures and training to
> support connection of this small, portable generator to the electrical
> distribution system in a manner that provides power to at least one
> train of igniters through temporary connections. In addition, these
> licensees have identified one or more additional fixed power sources
> that could be used to power one train of igniters through temporary
> electrical connections. The inspection focus is on the use of the
> portable generator as a backup power supply and associated equipment,
> procedures, and training.
>
> 2\. Assess the identified location of the temporary connection to
> verify the ability to reliably provide power to the igniters
> consistent with commitments.

04.02 Equipment Modifications

Consistent with applicable commitments, determine whether the equipment
necessary to provide backup power to the hydrogen igniters is available.
Where portable power supplies and temporary connections were selected,
determine the following:

> a\. The power supply can be transported from its storage location to
> the access location for providing power to the igniters using readily
> available equipment.
>
> b\. Fittings, cables, and power conditioning equipment necessary to
> provide power to the igniters are readily available and compatible
> with identified connection points on the power supply and in the
> internal power distribution system.
>
> c\. Unnecessary portions of the internal power distribution system can
> be separated from portions necessary to provide power to the igniters
> from the portable power supply.
>
> d\. The movement of the power supply and connection of necessary
> fittings and cables to provide backup power to the igniters can be
> completed within 3 hours.
>
> e\. The rating of the portable power supply is adequate to
> continuously power at least one train of igniters and the operating
> time is consistent with commitments.

04.03 Procedures

Determine that appropriate procedures have been established to govern
the provision of backup power to the igniters. Procedures written at the
level of severe accident management guidelines are acceptable for
installation and operation of portable equipment. Section 5 of NEI
94-01, Rev. 1 (Reference 10) provides guidance on an acceptable level of
detail for severe accident management procedures. Procedures should
address the decision to provide backup power to the igniters and the
steps required to provide the backup power. Determine that the
procedures include cautions against actuation of the igniters after
indications of severe core damage are present (e.g., very high airborne
radioactivity within containment that may be indicated by abnormally
high radiation levels adjacent to containment).

04.04 Training

Determine that a suitable training program has been established to train
selected staff in the actions necessary to provide backup power to the
igniters. Determine that the training provides appropriate guidelines
for initiation of backup power to the igniters.

04.05 Maintenance and Testing

Determine that maintenance and testing schedules that are consistent
with vendor recommendations have been established for portable and
permanently installed equipment. Determine that an initial operational
test has been completed to demonstrate the capability of portable power
supplies to provide power to the igniters.

2515/174-05 REPORTING REQUIREMENTS

The detailed responses to the inspection requirements specified in
Section 04.01 should be submitted electronically and forwarded to
NRR/DSS, to the attention of Steve Jones via e-mail to srj@nrc.gov
within 45 days after the completion of the TI.

Document inspection results in a resident inspectors' routine inspection
report. At a minimum, the inspectors should document the completion of
the TI, the dates of the inspection, and any findings in Section 4OA5,
"Other," of the integrated inspection report.

Any findings identified during this inspection should be processed and
documented in accordance with NRC IMC 0612. Significance of inspection
findings should be evaluated in accordance with applicable appendices of
NRC IMC 0609, "Significance Determination Process." Any noncompliance
resulting from this inspection should be evaluated and documented in
accordance with NRC Enforcement Policy (NUREG -1600) and Section 3.12 of
the NRC Enforcement Manual.

2515/174-06 COMPLETION SCHEDULE

This TI will be completed within 6 months following the implementation
date for the first unit at each site and no later than June 30, 2009.

The original scheduled implementation dates were: December 31, 2007, for
the Clinton, D.C. Cook, Sequoyah, and Watts Bar sites; April 31, 2008,
for the Grand Gulf, Perry, and River Bend sites; May 31, 2008, for the
first unit at the McGuire site (Unit 2); and May 31, 2009, for the first
unit at the Catawba site (Unit 2).

2515/174-07 EXPIRATION

This TI will expire August 31, 2009.

2515/174-08 CONTACT

Questions regarding the technical aspects of this TI should be addressed
to Steve Jones at 301-415-2712 or Donnie Harrison at 301-415-3587.

2515/174-09 STATISTICAL DATA REPORTING

All direct inspection effort expended on this TI is to be charged to
2515/174 for reporting by the Regulatory Information Tracking System
(RITS) with an IPE code of TI. All indirect inspection effort on this TI
is to be charged to a specific inspection report number with an IPE code
of TIP or TID for preparation and documentation, respectively.

2515/174-10 ORIGINATING ORGANIZATION INFORMATION

10.01 Organizational Responsibility

This TI was initiated by the Balance of Plant Branch (NRR/DSS/SBPB).

10.02 Resource Estimate

The estimated direct inspection effort to perform this TI is estimated
to be 40 hours per site. The TI should be performed by qualified
resident or regional inspectors.

10.03 Training

No specialized training is needed to perform inspection requirements in
this TI beyond

the basic training for inspectors (specified in IMC 1245, \"Inspector
Qualifications\").

2515/174-11 REFERENCES

1\. Regulatory Analysis: "Proposed Action to Address Generic Safety
Issue 189: 'Susceptibility of Ice Condenser and Mark III Containments to
Early Failure from Hydrogen Combustion during a Severe Accident'," May
24, 2005 (ADAMS Accession No.: ML051450060)

2\. Duke Energy Corporation, letter to the U.S. NRC from James R.
Morris, Vice President, Catawba Nuclear Station, March 8, 2007 (ADAMS
Accession No.: ML070790255).

3\. Indiana Michigan Power Company, letter to the U.S. NRC from Joseph
N. Jensen, Site Vice President, Donald C. Cook Nuclear Plant, February
9, 2007 (ADAMS Accession No.: ML070520400).

4\. Tennessee Valley Authority, letter to the U.S. NRC from Preston D.
Swafford, Senior Vice President, Nuclear Support, March 6, 2007 (ADAMS
Accession No.: ML070670149).

5\. FirstEnergy Nuclear Operating Company, letter to the U.S. NRC from
L. William Pearce, Vice President - Nuclear, February 26, 2007 (ADAMS
Accession No.: ML070660457) (Non-Publicly Available).

6\. Entergy Operations, Incorporated, letter to the U.S. NRC from Edward
D. Harris, Acting Director, Nuclear Safety Assurance, Grand Gulf Nuclear
Station, March 1, 2007 (ADAMS Accession No.: ML070720416) (Non-Publicly
Available).

7\. Entergy Operations, Incorporated, letter to the U.S. NRC from Rick
J. King, Director, Nuclear Safety Assurance, River Bend Station,
February 15, 2007 (ADAMS Accession No.: ML070520435).

8\. AmerGen Energy Company, LLC, letter to the U.S. NRC from Bryan
Hansen, Site Vice President, Clinton Power Station, February 28, 2007
(ADAMS Accession No.: ML072280266).

9\. Inspection Procedure 71111, "Reactor Safety - Initiating Events,
Mitigating Systems, Barrier Integrity," Attachment 71111.17, "Permanent
Plant Modifications," dated July 7, 2005.

10\. NEI 94-01, "Severe Accident Issue Closure Guidelines," December
1994 (ADAMS Accession No.: ML072850981).

END

ATTACHMENT 1

Revision History for TI 2515/7174

+--------+-------+---------------------+------+----------+------------+
| Comm   | Issue | Description of      | Trai | Training | Comment    |
| itment | Date  | Change              | ning | Co       | Resolution |
| Tr     |       |                     | Requ | mpletion | Accession  |
| acking |       |                     | ired | Date     | Number     |
| Number |       |                     |      |          |            |
+--------+-------+---------------------+------+----------+------------+
| N/A    | 02/   | This TI was         | None | N/A      | M          |
|        | 12/08 | developed to verify |      |          | L080030467 |
|        |       | licensee            |      |          |            |
|        | CN    | implementation of   |      |          |            |
|        | 0     | voluntary           |      |          |            |
|        | 8-007 | commitments for     |      |          |            |
|        |       | provision of backup |      |          |            |
|        |       | power to the        |      |          |            |
|        |       | containment         |      |          |            |
|        |       | hydrogen igniters.  |      |          |            |
+--------+-------+---------------------+------+----------+------------+
|        |       |                     |      |          |            |
+--------+-------+---------------------+------+----------+------------+