RA-15-057, Supplemental Response to Request for Additional Information Regarding Request for Extension to Comply with NRC Order EA-13-109: Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under..

Supplemental Response to Request for Additional Information Regarding Request for Extension to Comply with NRC Order EA-13-109: Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under..

ML15274A010
Person / Time
Site:	Oyster Creek
Issue date:	10/01/2015
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-13-109, RA-15-057, RS-15-184, TAC MF4352
Download: ML15274A010 (13)

Text

Exelon Generation @)

RS-15-184 RA-15-057 September 30, 2015 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Oyster Creek Nuclear Generating Station Renewed Facility Operating License No. DPR-16 NRC Docket No. 50-219

Subject:

Supplemental Response to Request for Additional Information Regarding Request for Extension to Comply with NRC Order EA-13-109: Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (TAC No. MF4352)

References:

1. NRC Order EA-13-109, Issuance of Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated June 6, 2013

2. Exelon Generation Company, LLC Letter to USNRC, Request for Extension to Comply with NRC Order EA-13-109, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions,"

dated June 2, 2014 (RS-14-081)

3. NRC letter to Exelon Generation Company, LLC, Request for Additional Information Regarding Request for Extension to Comply with NRC Order EA-13-109: Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated August 27, 2014

4. Exelon Generation Company, LLC Letter to USN RC, Response to Request for Additional Information Regarding Request for Extension to Comply with NRC Order EA-13-109: Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated September 26, 2014 (RS-14-243)

5. Exelon Generation Company, LLC Letter to USN RC, Supplemental Response to Request for Additional Information Regarding Request for Extension to Comply with NRC Order EA-13-109: Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated November 25, 2014 (RS-14-318)

On June 6, 2013, the Nuclear Regulatory Commission (NRC) issued Order EA-13-109 (Reference 1) to all licensees that operate boiling-water reactors with Mark I and Mark II containment designs. The Order was effective immediately and is applicable to Oyster Creek

U.S. Nuclear Regulatory Commission Supplemental Response to Request for Additional Information September 30, 2015 Page 2 Nuclear Generating Station (Oyster Creek). In Reference 2, Exelon Generation Company, LLC (EGC) requested an extension of the final compliance dates of Order EA-13-109 requirements in Section IV of NRC Order EA-13-109 concerning implementation of the Phase 1 (wetwell vent) and Phase 2 (drywell vent) at Oyster Creek until January 31, 2020. Also in Reference 2, EGC stated that it will submit a request for relief from NRC Order EA-13-109 no later than January 31, 2020 based upon the permanent shutdown condition of the plant at that time. In Reference 3, the NRC issued a request for additional information (RAI) in order for the NRC staff to complete its technical review of the EGC extension request. Reference 4 provided the EGG response to the NRC request for additional information. In Reference 5, EGC provided supplemental revised responses to the NRC RAI Nos. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, and 13 describing additional compensatory measures that will be implemented at Oyster Creek in order to provide enhanced containment vent capability and reliability.

As a result of subsequent discussions with the NRC, the purpose of this letter is to provide additional information regarding: (1) the seismic integrity of the existing hardened containment vent line located inside the Reactor Building, and (2) the additional evaluation and provisions being implemented to address potential combustible gas accumulation inside the main vent stack. The additional information is provided in Enclosure 1 to this letter and is addressed in supplemental revised responses to the NRC RAI Nos. 11 and 12 from Reference 3. The supplemental revised responses to these NRC RAls replace the corresponding RAI responses previously submitted in References 4 and 5. This additional information supports the enhanced containment vent capability and reliability and further reduction of severe accident risk at Oyster Creek for the period of the extension request.

This letter contains new regulatory commitments, which are identified in Enclosure 2 to this letter.

If you have any questions regarding this response, please contact David P. Helker at 610-765-5525.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 301h day of September 2015.

James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosures:

1. Oyster Creek Nuclear Generating Station - Supplemental Responses to Request for Additional Information Regarding Request for Extension to Comply with NRC Order EA-13-109: Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions

2. Summary of Regulatory Commitments

U.S. Nuclear Regulatory Commission Supplemental Response to Request for Additional Information September 30, 2015 Page 3 cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region I NRC Senior Resident Inspector - Oyster Creek Nuclear Generating Station NRC Project Manager, NRR - Oyster Creek Nuclear Generating Station Mr. John D. Hughey, NRR/JLD/JOMB, NRC Mr. Charles H. Norton, NRR/JLD/JOMB, NRC Manager, Bureau of Nuclear Engineering - New Jersey Department of Environmental Protection Mayor of Lacey Township, Forked River, NJ

Enclosure 1 Oyster Creek Nuclear Generating Station - Supplemental Responses to Request for Additional Information Regarding Request for Extension to Comply with NRC Order EA-13-109: Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions

Supplemental Response to Request for Additional Information Page 1 of 8 RAl-11 EA-13-109, Attachment2, Requirement 1.2.11: (NEI 13-02 Section 4.1.7)

The HCVS shall be designed and operated to ensure the flammability limits of gases passing through the system are not reached; otherwise, the system shall be designed to withstand dynamic loading resulting from hydrogen deflagration and detonation.

Question Provide a description of the differences, if any, between the guidance in NEI 13-02, Section 4.1.7, and the actual, physical configuration and/or capabilities of the containment venting system which will be in operation during the requested period of extension. Include a description of compensatory measures, if any, which will be utilized to achieve equivalent or similar capabilities as required by the order and described in the guidance during the requested period of extension.

Response

The Oyster Creek Generic Letter (GL) 89-16 hardened vent path was not originally designed to ensure that the flammability limits of gases passing through the system are not reached or designed to withstand dynamic loading resulting from hydrogen deflagration and detonation. The following paragraphs address the concern of a hydrogen detonation.

The Oyster Creek GL 89-16 hardened vent path is discussed in the response to RAls 1 and 3 in Reference 6. The design has a manually operated butterfly valve (V-23-358) downstream of the containment isolation valves that is accessible from ground level (at the northeast corner of the Reactor Building) through reach rods penetrating a radiation shield. This design allows for continuous outflow from the pipe to reduce the risk of outside air being drawn into the piping by opening and retaining open the containment isolation valves and throttling through V-23-358.

The main stack is a seismic 1 conically shaped concrete structure (Reference 1). The stack inside diameter at its 35 foot elevation floor is approximately 26 feet diameter, and the stack top is 8.5 feet inside diameter. The top of the stack is at elevation 391 feet, yielding an inside height of 356 feet between the floor and the top. The hardened vent line discharges into this stack through an 8-inch nominal diameter, 90° elbow with the discharge pointing vertically upward. The elbow is about 3 feet above a concrete floor on the stack and near the inside wall of the stack. This elbow also has a 2-inch diameter hole to allow condensate drainage, but it would also vent some of the fluid.

The containment pressure during severe accident venting will be close to the primary containment pressure limit (PCPL) of 55 psig, the torus will be at saturated conditions, and the vented fluid temperature will be approximately 300°F. Consequently, the initial high flow velocity exiting the vent pipe elbow and the buoyancy forces for the hydrogen and steam both add to the upward flow of the vented fluid.

Supplemental Response to Request for Additional Information Page 2 of 8 There are no internal obstructions in the stack to hinder vertical flow out of the stack. As noted previously, once venting is started, there will be a continuous outflow through the stack.

Venting will only be from the torus. The vented fluids initially consist of nitrogen and steam.

Following core damage progression and depletion of the heavier nitrogen, the vented fluid consists of steam and hydrogen. The assumed limiting hydrogen concentration is 40% by volume (Reference 5) with the balance being steam. This condition (60% steam, 40% hydrogen, a 1.5 ratio of steam to hydrogen) represents the limiting case for venting into the stack.

Per References 2 and 3, a steam concentration above approximately 40% in an air, hydrogen, and steam environment results in "steam-inerting" that eliminates the potential for hydrogen detonation. Steam concentrations below 40% remain beneficial since the steam significantly reduces the sensitivity of the mixture to detonate and it reduces the range of hydrogen concentrations that would detonate. The steam and hydrogen discharged into the stack are considered well mixed due to the flow through a considerable length of 8-inch and 10-inch piping.

In order for the vented fluids to reach a detonable condition, the steam to hydrogen ratio has to be reduced from the initial value of 1.5 to less than 0.40. This would require a steam reduction of 73% in the vented fluid. Consequently, at the pipe exhaust into the stack there is a considerable initial excess of steam to prevent detonation.

The presence of steam also significantly reduces the likelihood of detonation even with a detonable mixture present. Reference 2 states:

"Stoichiometric mixtures with steam concentrations of 10, 20, and 30 percent increase the experimental cell width by factors of approximately 4, 23.6, and 92.8, respectively, compared to stoichiometric mixtures without steam. This corresponds to decreasing the likelihood of a detonation for these mixtures by factors of 64, 13, 100, and 800,000."

There are no electrical or electronic components in the stack that could provide a spark. Given that there would be significant steam flow into the stack, the stack inside surface is expected to be moist further reducing the possibility of an ignition source on the stack surface.

To provide additional assurance that detonation will not occur in the stack, Oyster Creek will open a hatch on the concrete floor just below the hardened vent connection to create a thermal stack effect. The hardened vent discharge on the inside of the stack will create a significant temperature difference between the inside of the stack and the outside air (below the hatch opening), thus creating a significant natural draft flow. Procedures will require that the hatch be manually opened prior to the start of venting. The hatch is accessible from ground level through a permanently installed approximately 1O foot high ladder. Opening the hatch only requires removing two wing nuts. As part of this effort, a modification (e.g., a diverter plate) will be performed to ensure that any downward flow from the 2-inch diameter drain hole on the hardened vent elbow does not interfere with the natural draft through the hatch.

Two bounding flow mixing conditions between the natural draft air and vented fluids are considered. The first condition assumes that the steam and hydrogen plume does not significantly mix with the cooler air due to the limited plume transient time resulting from both the initial upward velocity plus the plume buoyancy. With this assumption the hydrogen is maintained inerted by the steam, which even with some condensation is expected to remain above 40%.

The second condition is that as the hydrogen and steam mix with the stack air, it causes dilution

Supplemental Response to Request for Additional Information Page 3 of 8 of both the steam and hydrogen concentrations. Reference 4 estimated the hydrogen, steam, and natural draft flow in the stack for various hydrogen concentrations in the vent pipe assuming full mixing with the air flow, as listed below.

I

% Hydrogen j

in Steam by I Volume from Containment 0% 5% 10% 15% 20% 25% 30% 35% 40% I 45% 50%

% Hydrogen  !

in Stack 0% 3% 6% 9% 12% 15% 19% 22% 25% i I 29% 33%

% Steam in Stack 53% 51% 49% 47% 45% 42% 40% 37% 35% I 32% 30%

% Air in Stack 47% 46% 45% 44% 43% 43% 42% 41% 40% ! 39% 38%

As shown on the above table, with up to 30% hydrogen flow from the containment, the steam concentration in the stack remains above 40% and detonation is precluded due to steam inerting.

Between 30% and 50% hydrogen flow from the containment, there remains a sufficient steam concentration in the stack so that the hydrogen, air, and steam mixture remains outside the detonation region. Note that Reference 4 evaluated up to 50% hydrogen from the containment, which is above the 40% value of Reference 5. When determining detonability in the stack with steam below 40%, Reference 4 used Figure 2-16 of Reference 7.

In summary, when the hardened vent fluid is discharged into the stack, the vented fluid will contain a significant amount of saturated steam. Due to the upward discharge velocity and the buoyancy of the steam, the residence time within the stack for the vented fluids is very short which would minimize the loss of steam inerting due to condensation. Adding natural draft is anticipated to provide added assurances by reducing the amount of hydrogen present in the stack.

References

1. UFSAR 3.5.2, Rev. 18, Structures, Systems and Components to be Protected from Externally Generated Missiles

2. NUREG/CR-5525, "Hydrogen-Air-Diluent Detonation Study for Nuclear Reactor Safety Analyses", published January 1991, prepared by Sandia National Laboratories

3. NKS-9, "On Detonation Dynamics in Hydrogen-Air-Steam Mixtures: Theory and Application to Olkiluoto Reactor Building", published February 2000, prepared by the Nordic Nuclear Safety Research

4. "Evaluation of Hydrogen Concentration with the Stack", AIR A2383779 Evaluation 02, dated September 25, 2015

5. NEI 13-02, R1, "Industry Guidance For Compliance With Order EA-13-109", dated April 2015, Section 2.4.5.3.2

6. Exelon Generation Company, LLC Letter to USN RC, Response to Request for Additional Information Regarding Request for Extension to Comply with NRC Order EA-13-109:

Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated September 26, 2014 (RS-14-243)

Supplemental Response to Request for Additional Information Page 4 of 8

7. NUREG/CR-2726, "Light Water Reactor Hydrogen Manual," SAND82-1137, R3, published August 1983, prepared by Sandia National Laboratories

Supplemental Response to Request for Additional Information Page 5 of 8 RAl-12 EA-13-109, Attachment 2, Requirement 2.2: (NEI 13-02 Section 5.2 and 5.3)

All other HCVS components shall be designed for reliable and rugged performance that is capable of ensuring HCVS functionality following a seismic event. These items include electrical power supply, valve actuator pneumatic supply and instrumentation (local and remote) components.

In addition, the OCNGS UFSAR Section 6.2.7.4 describes the Failure Modes and Effects Analysis (FMEA) of the Hardened Vent System and states in part:

The 1O" vent pipe which is not seismic, is provided with anti-fall down pipe supports. In the event of a seismic event, failure of the hardened vent pipes (8" and 1O"} may occur.

Question Given the severe accident conditions associated with the Order, address the potential failure of the hardened vent pipes in the response to RAl-12 below.

Provide a description of the differences, if any, between the guidance in NEI 13-02, Section 5.2 and 5.3, and the actual, physical configuration and/or capabilities of the containment venting system which will be in operation during the requested period of extension. Include a description of compensatory measures, if any, which will be utilized to achieve equivalent or similar capabilities as required by the Order and described in the guidance during the requested period of extension.

Response

NEI 13-02 Sections 5.2.1 and 5.3.1.1 The containment isolation valves V-23-13, V-23-14, V-23-15 and V-23-16, operators, containment penetration piping, valve position limit switches, pilot solenoids, power supplies, accumulators and the accumulators' piping/tubing are qualified to seismic class 1 (References 2 and 3). This complies with NEI 13-02, Sections 5.2.1 and 5.3.1.1. HCVS isolation valves and selected associated components are being added to the Expedited Seismic Equipment List (ESEL) to be evaluated under the Expedited Seismic Evaluation Process (ESEP).

NEI 13-02 Sections 5.2.2 and 5.3.1.2 The portions of the Oyster Creek NRC GL 89-16 external hardened vent path that are downstream of the primary containment penetrations consist of 8-inch and 10-inch nominal diameter piping. The 8-inch nominal diameter hardened vent path, which is inside the Reactor Building from the containment penetration to the Reactor Building wall, was part of the original Oyster Creek design for the nitrogen inerting system. The 8-inch nominal diameter piping original analysis did not include any seismic loads (Reference 4). This line was re-evaluated (Reference

1) using the AutoPIPE computer program which is a comprehensive, finite element software tool

Supplemental Response to Request for Additional Information Page 6 of 8 for pipe stress design and analysis. The reanalysis confirmed that the existing vent and purge line will remain available for torus venting following an Oyster Creek safe shutdown earthquake (SSE) event. The maximum computed pipe stress for the seismic (SSE) load combination was less than 25 KSI. This is well below the 36 KSI factored stress allowable of the pipe material.

This criteria is consistent with Oyster Creek Station requirements for occasional (sustained +

SSE) loadings. The seismic load case conservatively considers that the piping is at the design pressure of 100 psig. Vent line hanger and supports (considered active) were confirmed by the analysis to have faulted loads that are still within their design capacities during the SSE condition.

Maximum valve accelerations under SSE conditions were also found to be less than 1 g, which is well below acceptance criteria. The conclusion of this numerical calculation is that the existing Nitrogen Vent and Purge I HCVS piping inside the Reactor Building can be considered "Seismically Robust" and will remain available after an SSE to vent the containment if this becomes necessary following an Extended Loss of AC Power (ELAP).

The 10-inch nominal diameter externally routed hardened vent path from the Reactor Building wall to the main stack was added in 1992 as part of the NRG GL 89-16 modification and was designed to anti-falldown seismic criteria (Reference 4). However, a review of the original design basis AutoPIPE analysis for this vent line determined that the maximum computed pipe stress for the occasional load combination (sustained+ SSE) was less than 7 KSI conservatively assuming that the piping is at the design pressure of 100 psig. Vent line hanger and supports (considered active) were confirmed by the analysis to have faulted loads that are still within their design capacities during the SSE condition. The only valve on the 10-inch line is the manual control valve (V-23-358) located at ground level. The conclusion is that the existing piping outside the Reactor Building can be considered "Seismically Robust" and will remain available after an SSE to vent the containment.

Furthermore, the Electric Power Research Institute (EPRI) has documented the effects of strong earthquakes of magnitude 5.9 to 7.6 in California on various facilities of different vintages in many reports such as NP-7126 (Reference 5), NP-7500-SL (Reference 6), TR-103477 (Reference 7),

and TR-103454 (Reference 8).

These reports concluded that welded steel piping generally exhibited excellent earthquake performance, even for piping with only sporadic provisions for seismic loads in pipe support systems. As described in the Oyster Creek UFSAR, Section 2.5.2.3 (Reference 9), the "Seismic Probability Map of the United States" (U.S. Coast and Geodetic Survey) assigns New Jersey to seismic Zone 1 (minor damage) as compared with seismic Zone 3 (major damage) for California.

The seismicity of the general region of the Oyster Creek Site is sufficiently low that it would be expected to have a low intensity of ground motion. The shocks in this region are too small to be listed in "Seismicity of the Earth" by Gutenberg and Richter, and the U.S. Coast and Geodetic Survey publication does not provide information on the magnitudes of the shocks.

NEI 13-02 Section 5.2.3 "The components including instrumentation external to a seismic category 1 (or equivalent building or enclosure) should be designed to meet the external hazards that screen in for the plant as defined in guidance NEI 12-06, as endorsed by JLD-ISG-2012-01, for NRG Order EA-12-049."

Supplemental Response to Request for Additional Information Page 7 of 8 Oyster Creek screens in for Seismic, External Flooding, Snow, Ice and Extreme Cold, Extreme High Temperature, and High Wind Hazard. The Oyster Creek HCVS components satisfy the requirements of NEI 12-06 as described below:

• Seismic is addressed in RAl-12 above.

• External Flooding: The flooding IPEEE results (Reference 11) indicate that HCVS components external to a seismic category 1 structure will not be affected by the most limiting flooding conditions.

• Snow, Ice, and Extreme Cold: Snow and Ice will be addressed by the compensatory measure procedure changes listed below.

• Extreme High Temperature: The highest recorded temperature documented in the UFSAR for southern New Jersey was listed as 106°F (Reference 10). The components external to a seismic category 1 structure will not be affected by the extreme high temperature.

• High Wind Hazards: Wind Hazards are addressed in the compensatory measure procedure changes listed below and as addressed in RAl-3 (Reference 12).

NEI 13-02 Sections 5.3.1 .3 and 5.3.1.4 The compensatory HCVS modification(s) described in RAl-1, 2, 4, 5, 6, 7, and 8 (Reference 12) comply with NEI 13-02, Section 5.2, Seismic and External Conditions and NEI 13-02, Section 5.3, Quality Requirements. The hardened vent piping, inside and outside of the Reactor Building, was evaluated using AutoPIPE stress analysis code and confirmed to remain functional following the Oyster Creek SSE.

Compensatory Measures Oyster Creek procedure OP-OC-108-109-1001, "Severe Weather Preparation T&RM for Oyster Creek," will be revised to ensure a snow and ice removal plan is in place to provide access to the manual valve station for the HCVS located at the northeast corner of the Reactor Building. The procedure will also include steps to ensure the northeast corner of the Reactor Building near the HCVS manual valve station is clear of loose objects that could become wind driven missiles. The procedure will be implemented by the OC1 R26 Refueling Outage (Fall 2016).

Similar Capabilities The original design basis for Oyster Creek includes redundant isolation condenser trains that are designed to Seismic Class 1 criteria and do not require AC power for operation. The original design basis for the isolation condenser system (ICS) includes a station black-out (SBO) event.

In response to NRC Order EA-12-049, water make-up sources will be added to the isolation condenser shell-side for an ELAP event, which are not dependent on permanently installed equipment. The NRC Order EA-12-049 actions will provide increased availability of the Oyster Creek Station DC power required to maintain isolation condenser system operability. The NRC Order EA-12-049 FLEX modifications are being implemented in the OC1 R26 Refueling Outage (Fall 2016) in accordance with the Order completion milestone schedule. Accordingly, following a seismic event and an Extended Loss of AC Power (ELAP) event, the isolation condenser system would be expected to remain available. ICS usage prevents any significant containment pressurization since it releases the reactor decay heat directly to the outside atmosphere. The RPV steam condensed in the isolation condenser is returned to the RPV, thereby minimizing the

Supplemental Response to Request for Additional Information Page 8 of 8 loss of RPV inventory. The availability of Seismic Class 1 redundant isolation condenser trains following an ELAP prevents any significant containment pressurization and, by returning the condensate to the reactor, reduces the risk of core damage. Accordingly, the isolation condenser system would be used following a seismic event and an ELAP instead of the hardened vent path for decay heat removal and, as such, provides equivalent or similar capabilities.

References

1. C-1302-854-E310-002, Piping Analysis for Nitrogen Purge Line Connected to the Hardened Vent System, Revision O, dated 7/30/2015

2. C-1302-822-5320-044, Hardened Vent Modification Seismic Support for Air Accumulators

3. SE-402968-001, Rev 2, Hardened Vent Modification

4. C-1302-822-5320-041, Rev O. Hardened Vent Piping

5. EPRI NP-7126, "The October 1, 1987, Whittier Earthquake: Effects on Selected Power, Industrial, and Commercial Facilities", prepared by EOE Engineering, December 1990.

6. EPRI NP-7500-SL, "The October 17, 1989, Loma Prieta Earthquake: Effects on Selected Power and Industrial Facilities", prepared by EOE Engineering, September 1991.

7. EPRI Report TR-103477, "The Cape Mendocino Earthquake Sequence of April 25 and 26, 1992: Effects on Electric Power Facilities", prepared by EOE International, November 1994.

8. EPRI Report TR-103454, "The June 28, 1992, Landers and Big Bear Earthquakes: Effects on Power and Industrial Facilities, prepared by EOE Engineering, December 1993

9. Oyster Creek UFSAR Section 2.5.2.3

10. Oyster Creek UFSAR, Table 2.3-2

11. Oyster Creek UFSAR Section 2.4.2.1

12. Exelon Generation Company, LLC Letter to USNRC, Supplemental Response to Request for Additional Information Regarding Request for Extension to Comply with NRG Order EA-13-109: Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated November 25, 2014 (RS-14-318)

Enclosure 2

SUMMARY

OF REGULATORY COMMITMENTS The following table identifies commitments made in this document. (Any other actions discussed in the submittal represent intended or planned actions. They are described to the NRC for the NRC's information and are not regulatory commitments.)

COMMITTED COMMITMENT TYPE COMMITMENT DATE OR ONE-TIME ACTION PROGRAMMATIC "OUTAGE" (Yes/No) (Yes/No)

1. To provide additional assurance that Prior to startup detonation will not occur in the stack, Oyster from Creek will open a hatch on the concrete floor OC1 R26 Refuel just below the hardened vent connection to Outage No Yes create a thermal stack effect. Procedures (Fall 2016) will require that the hatch be manually opened prior to the start of venting.

2. A modification (e.g., a diverter plate) will be Prior to startup performed to ensure that any downward flow from from the 2-inch diameter drain hole on the OC1 R26 Refuel Yes No hardened vent elbow does not interfere with Outage the natural draft through the hatch. (Fall 2016)

3. Oyster Creek procedure OP-OC-108-109-1001, "Severe Weather Preparation T&RM for Oyster Creek," will be revised to ensure a snow and ice removal plan is in place to provide access to the manual valve station Prior to startup for the HCVS located at the northeast corner from of the Reactor Building. The procedure will OC1 R26 Refuel No Yes also include steps to ensure the northeast Outage corner of the Reactor Building near the (Fall 2016)

HCVS manual valve station is clear of loose objects that could become wind driven missiles. (Note: This is a previous commitment from cover letter Reference 5.)