ML15006A319

Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-13-109 (Severe Accident Capable Hardened Vents)

ML15006A319
Person / Time
Site:	Duane Arnold
Issue date:	02/11/2015
From:	Halter M Japan Lessons-Learned Division
To:	Vehec T NextEra Energy Duane Arnold
Lee B, NRR/JLD, 415-2916
References
EA-13-109, TAC MF4391
Download: ML15006A319 (39)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 11, 2015 Mr. Thomas A. Vehec Site Vice President NextEra Energy Duane Arnold, LLC Duane Arnold Energy Center 3277 DAEC Road Palo, lA 52324-9785

SUBJECT:

DUANE ARNOLD ENERGY CENTER -INTERIM STAFF EVALUATION RELATING TO OVERALL INTEGRATED PLAN IN RESPONSE TO PHASE 1 OF ORDER EA-13-109 (SEVERE ACCIDENT CAPABLE HARDENED VENTS) (TAC NO. MF4391)

Dear Mr. Vehec:

By letter dated June 6, 2013, the U.S. Nuclear Regulatory Commission (NRC) issued Order EA-13-1 09, "Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions" (Agencywide Documents Access and Management System (ADAMS) Accession No. ML13143A334). By letter dated June 25, 2014 (ADAMS Accession No. ML14182A423), NextEra Energy Duane Arnold, LLC (NextEra),

submitted its Overall Integrated Plan (OIP) for Duane Arnold Energy Center (DAEC) in response to Phase 1 of Order EA-13-1 09. By letter dated December 10, 2014 (ADAMS Accession No. ML14349A324), Next Era submitted its first six-month status report for DAEC in response to Order EA-13-109. Any changes to the compliance method described in the OIP will be reviewed as part of the ongoing audit process.

NextEra's OIP appears consistent with the guidance found in Nuclear Energy Institute (NEI) 13-02, Revision 0 as endorsed, in part, by the NRC's Japan Lessons-Learned Project Directorate (JLD) Interim Staff Guidance (ISG) JLD-ISG-2013-02, as an acceptable means for implementing the requirements of Phase 1 of Order EA-13-1 09. This conclusion is based on satisfactory resolution of the open items detailed in the enclosed Interim Staff Evaluation. This evaluation only addressed consistency with the guidance. Any plant modifications will need to be conducted in accordance with plant engineering change processes and consistent with the licensing basis.

T. Vehec If you have any questions, please contact Charles Norton, Project Manager, at 301-415-7818 or at Charles.Norton@nrc.gov.

Mandy K. Halter, Acting Chief Orders Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket No. 50-331

Enclosure:

Interim Staff Evaluation cc w/encl: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 INTERIM STAFF EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO ORDER EA-13-109 PHASE 1, MODIFYING LICENSES WITH REGARD TO RELIABLE HARDENED CONTAINMENT VENTS CAPABLE OF OPERATION UNDER SEVERE ACCIDENT CONDITIONS NEXTERA ENERGY DUANE ARNOLD, LLC DUANE ARNOLD ENERGY CENTER DOCKET NO. 50-331

1.0 INTRODUCTION

By letter dated June 6, 2013, the U.S. Nuclear Regulatory Commission (NRC, or Commission) issued Order EA-13-1 09, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions" [Reference 1].

The order requires licensees to implement its requirements in two phases. In Phase 1, licensees of boiling-water reactors (BWRs) with Mark I and Mark II containments shall design and install a venting system that provides venting capability from the wetwell during severe accident (SA) conditions. In Phase 2, licensees of BWRs with Mark I and Mark II containments shall design and install a venting system that provides venting capability from the drywell under severe accident conditions, or, alternatively, those licensees shall develop and implement a reliable containment venting strategy that makes it unlikely that a licensee would need to vent from the containment drywell during severe accident conditions. 1 The purpose of the staff's review, as documented in this interim staff evaluation (ISE) is to provide an interim evaluation of the Overall Integrated Plan (OIP) for Phase 1 of Order EA 109. Phase 1 of Order EA-13-1 09 requires that BWRs with Mark I and Mark II containments 1

This ISE only addresses the licensee's plans for implementing Phase 1 of Order EA-13-1 09. While the licensee's OIP makes reference to Phase 2 issues, those issues are not being considered in this evaluation. Issues related to Phase 2 of Order EA-13-1 09 will be considered in a separate interim staff evaluation at a later date.

Enclosure

design and install a severe accident capable hardened containment vent system (HCVS) that provides venting capability from the wetwell during severe accident conditions, using a vent path from the containment wetwell to remove decay heat, vent the containment atmosphere (including steam, hydrogen, carbon monoxide, non-condensable gases, aerosols, and fission products), and control containment pressure within acceptable limits. The HCVS shall be designed for those accident conditions (before and after core damage) for which containment venting is relied upon to reduce the probability of containment failure, including accident sequences that result in the loss of active containment heat removal capability or extended loss of alternating current (ac) power (ELAP).

By letter dated June 25, 2014 [Reference 2], NextEra Energy Duane Arnold, LLC (the licensee, NextEra) provided the OIP for Duane Arnold Energy Center (DAEC) for compliance with Phase 1 of Order EA-13-109. The OIP describes the licensee's currently proposed modifications to systems, structures, and components, new and revised guidance, and strategies that it intends to implement in order to comply with the requirements of Order EA-13-1 09.

2.0 REGULATORY EVALUATION

Following the events at the Fukushima Dai-ichi nuclear power plant on March 11, 2011, the NRC established a senior-level agency task force referred to as the Near-Term Task Force (NTTF). The NTTF was tasked with conducting a systematic and methodical review of the NRC regulations and processes and determining if the agency should make improvements to these programs in light of the events at Fukushima Dai-ichi. As a result of this review, the NTTF developed a set of recommendations, documented in SECY-11-0093, "Near-Term Report and Recommendations for Agency Actions Following the Events in Japan," dated July 12, 2011

[Reference 3]. These recommendations were enhanced by the NRC staff following interactions with stakeholders. Documentation of the NRC staff's efforts is contained in the Commission's Staff Requirements Memorandum (SRM) SECY 0124, "Recommended Actions to be Taken without Delay from the Near-Term Task Force Report," dated September 9, 2011 [Reference 4]

and SECY 0137, "Prioritization of Recommended Actions to be Taken in Response to Fukushima Lessons Learned," dated October 3, 2011 [Reference 5].

As directed by the Commission's SRM for SECY-11-0093 [Reference 6], the NRC staff reviewed the NTTF recommendations within the context of the NRC's existing regulatory framework and considered the various regulatory vehicles available to the NRC to implement the recommendations. SECY-11-0124 and SECY-11-0137 established the NRC staff's prioritization of the recommendations based upon the potential safety enhancements.

On February 17,2012, the NRC staff provided SECY-12-0025, "Proposed Orders and Requests for Information in Response to Lessons Learned from Japan's March 11, 2011, Great Tohoku Earthquake and Tsunami" [Reference 7], to the Commission, including the proposed order to implement the installation of a reliable HCVS for Mark I and Mark II containments. As directed by SRM-SECY-12-0025 [Reference 8], the NRC staff issued Order EA-12-050, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents" [Reference 9], which requires licensees to install a reliable HCVS for Mark I and Mark II containments.

While developing the requirements for Order EA-12-050, the NRC acknowledged that questions remained about maintaining containment integrity and limiting the release of radioactive

materials if the venting systems were used during severe accident conditions. The NRC staff presented options to address these issues for Commission consideration in SECY 0157, "Consideration of Additional Requirements for Containment Venting Systems for Boiling Water Reactors with Mark I and Mark II Containments" [Reference 10]. In the SRM for SECY 0157

[Reference 11], the Commission directed the staff to issue a modification to Order EA-12-050, requiring licensees with Mark I and Mark II containments to "upgrade or replace the reliable hardened vents required by Order EA-12-050 with a containment venting system designed and installed to remain functional during severe accident conditions." The NRC staff held a series of public meetings following issuance of SRM SECY 0157 to engage stakeholders on revising the order. Accordingly, by letter dated June 6, 2013, the NRC issued Order EA-13-1 09, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Performing under Severe Accident Conditions."

Order EA-13-1 09, Attachment 2 requires that BWRs with Mark I and Mark II containments shall have a reliable, severe accident capable HCVS. This requirement shall be implemented in two phases. In Phase 1, licensees of BWRs with Mark I and Mark II containments shall design and install a venting system that provides venting capability from the wetwell during severe accident conditions. Severe accident conditions include the elevated temperatures, pressures, radiation levels, and combustible gas concentrations, such as hydrogen and carbon monoxide, associated with accidents involving extensive core damage, including accidents involving a breach of the reactor vessel by molten core debris. In Phase 2, licensees of BWRs with Mark I and Mark II containments shall design and install a venting system that provides venting capability from the drywell under severe accident conditions, or, alternatively, those licensees shall develop and implement a reliable containment venting strategy that makes it unlikely that a licensee would need to vent from the containment drywell during severe accident conditions.

On November 12, 2013, the Nuclear Energy Institute (NEI) issued NEI 13-02, "Industry Guidance for Compliance with Order EA-13-1 09," Revision 0 [Reference 12] to provide guidance to assist nuclear power reactor licensees with the identification of measures needed to comply with the requirements of Phase 1 of the HCVS order. On November 14, 2013, the NRC staff issued Japan Lessons-Learned Project Directorate (JLD) interim staff guidance (ISG) JLD-ISG-2013-02, 'Compliance with Order EA-13-109, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Performing under Severe Accident Conditions"' [Reference 13], endorsing, in part, NEI 13-02, Revision 0, as an acceptable means of meeting the requirements of Phase 1 of Order EA-13-1 09, and published a notice of its availability in the Federal Register (FR) [78 FR 70356]. Licensees are free to propose alternate methods for complying with the requirements of Phase 1 of Order EA-13-1 09.

By letter dated May, 27, 2014 [Reference 14], the NRC notified all BWR Mark I and Mark II Licensees that the staff will be conducting audits of the implementation of Order EA-13-1 09.

This letter described the audit process to be used by the staff in its review of the information contained in licensee's submittals in response to Phase 1 of Order EA-13-1 09.

3.0 TECHNICAL EVALUATION

DAEC is a single unit General Electric BWR with a Mark I containment system with an existing containment venting system installed in accordance with Generic Letter 89-16, "Installation of a Hardened Wetwell Vent" (Agencywide Documents Access and Management System (ADAMS)

Accession No. ML060760371). To implement Phase 1 (HCVS) of Order EA-13-109, NextEra plans to use the existing containment penetration that supports normal wetwell venting to the standby gas treatment system. New piping will be routed in the reactor building and will exit through the reactor building roof. As part of its review of the submitted OIP, the NRC staff held clarifying discussions with NextEra in evaluating the licensee's plans for addressing wetwell venting during beyond-design-basis external events (BDBEEs) and SAs.

3.1 GENERAL INTEGRATED PLAN ELEMENTS AND ASSUMPTIONS 3.1.1 Evaluation of Extreme External Hazards Extreme external hazards for DAEC were evaluated in the DEAC OIP in response to Order EA-12-049 (Mitigation Strategies) [Reference 15]. In the DAEC ISE relating to Mitigating Strategies

[Reference 16], NRC staff documented an analysis of NextEra's extreme external hazards evaluation. The following extreme external hazards screened in: Seismic, External Flooding, Storms with High Winds, Snow and Ice, Low Temperatures, and Extreme High Temperatures.

No extreme external hazards were screened out. Based on DAEC not excluding any external hazard from consideration, the NRC Staff determined that NextEra appears to have identified the appropriate external hazards for consideration in the design of HCVS.

3.1.2 Assumptions On page 4 of the DAEC OIP, NextEra adopted a set of generic assumptions associated with Order EA-13-1 09 Phase 1 actions. The staff determined that the set of generic assumptions appear to establish a baseline for HCVS evaluation consistent with the guidance found NEI 13-02, as endorsed, in part, by JLD-ISG-2013-02 as an acceptable method to implement the requirements of Order EA-13-109.

The staff reviewed the one DAEC plant-specific HCVS related assumption:

PLT-1. The rupture disk, if retained, in the final design will be manually breeched if desired for anticipatory venting to allow establishing a containment vent path when containment pressure is approximately 10 PSIG (Approximately 3.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />) Reference 32 [of the OIP].

The staff determined that the plant specific assumption does not appear to deviate from the guidance found in NEI 13-02, as endorsed, in part, by JLD-ISG-2013-02 as an acceptable method to implement the requirements of Order EA-13-1 09. The licensee identified the need to confirm that secondary containment bypass leakage is acceptable without an installed rupture disk in the HCVS flow path.

Open Item: Make available for NRC staff audit, documentation of licensee confirmation that secondary containment leakage is acceptable without an installed rupture disk or that an appropriate rupture disk, including procedures for rupture during HCVS operation, is included in the HCVS design.

3.1.3 Compliance Timeline and Deviations Page 4 of the OIP states the following:

Compliance will be attained for [DAEC] with no known deviations to the guidelines in JLD-ISG-2013-02 and NEI 13-02 for each phase as follows:

• Phase I (wetwell): by the startup from the second refueling outage that begins after June 30, 2014, or June 30, 2018, whichever comes first. Currently scheduled for 41h Quarter 2016.

• Phase 2: Later If deviations are identified at a later date, then the deviations will be communicated in a future 6 month update following identification.

DAEC's schedule for Phase 1 of Order EA-13-1 09 complies with the requirements of the order.

DAEC did not provide an explicit schedule for Phase 2 implementation; however, DAEC did not identify deviations from the required schedule. Therefore, the staff concludes that the schedule appears to be in compliance with Order EA-13-1 09 requirements.

Regarding other deviations, DAEC did not identify any. However, the staff has identified one deviation from the guidance found in NEI 13-02, as endorsed, in part, by JLD-ISG-2013-02 as an acceptable method to implement the requirements of Order EA-13-1 09. The deviation pertains to the Institute of Electrical and Electronic Engineers (IEEE) standard used by DAEC for instrumentation seismic qualification and is discussed further in section 3.2.2.9, "Component Qualification," of this ISE.

Summary, Section 3.1:

The licensee's described approach to General Integrated Plan Elements and Assumptions if implemented as described in Section 3.1, and assuming acceptable resolution of any open items identified here or as a result of licensee alterations to their proposed plans, appears to be consistent with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-109.

3.2 BOUNDARY CONDITIONS FOR WETWELL VENT 3.2.1 Sequence of Events (SOE)

Order EA-13-1 09, Sections 1.1.1, 1.1.2, and 1.1.3, state that:

1.1.1 The HCVS shall be designed to minimize the reliance on operator actions.

1.1.2 The HCVS shall be designed to minimize plant operators' exposure to occupational hazards, such as extreme heat stress, while operating the HCVS system.

1.1.3 The HCVS shall also be designed to account for radiological conditions that would impede personnel actions needed for event response.

Page 7 of the OIP states the following:

The operation of the HCVS will be designed to minimize the reliance on operator actions in response to hazards listed in Part 1 [of the OIP]. Immediate operator actions will be completed by plant personnel and will include the capability for remote-manual initiation from the HCVS control station. A list of the remote manual actions performed by plant personnel to open the HCVS vent path can be found in the following table (2-1) [of the OIP]. A HCVS Extended Loss of AC Power (ELAP) Failure Evaluation table, which shows alternate actions that can be performed, is included in Attachment 4 [of the OIP].

NRC staff reviewed the Remote Manual Actions (Table 2-1 of the OIP) and concluded that these actions appear to consider minimizing the reliance on operator actions. The actions appear consistent with the types of actions described in the guidance found in NEI 13-02, as endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-109. NRC staff reviewed the Wetwell HCVS Failure Evaluation Table (Attachment 4 of the OIP) and determined the actions described appear to adequately address all the failure modes listed in the guidance provided by NEI 13-02, which include: loss of normal ac power, long term loss of batteries, loss of normal pneumatic supply, loss of alternate pneumatic supply, and solenoid operated valve failure.

The staff reviewed the three cases contained in the SOE timeline [Attachment 2 of the OIP] and determined that the three cases appropriately bound the conditions for which the HCVS is required. These cases include: successful FLEX implementation with no failure of reactor core isolation cooling (RCIC); late failure of RCIC leading to core damage; and failure of RCIC to inject at the start of the event. The timelines accurately reflect the progression of events as described in the DAEC FLEX OIP [Reference 17], SECY-12-0157 [Reference 10], and State-of-the-Art Reactor Consequence Analyses (SOARCA) [Reference 18].

The NRC staff reviewed the licensee's discussion of time constraints on page 8 of the OIP. The time constraints establish when the HCVS must be initiated and when supplemental compressed gas for motive power and supplemental electrical power (FLEX) must be supplied.

The staff confirmed that the time constraints identified appear to be appropriately derived from the time lines developed in Attachment 2 of the OIP, and therefore are consistent with the guidance found in NEI 13-02, as endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09.

The NRC staff reviewed the discussion of radiological and temperature constraints on page 9 of the OIP and determined that NextEra addressed radiological and temperature considerations at the locations identified to date where manual actions are necessary to operate HCVS. DAEC has not identified all locations where operator actions need to be performed and therefore has not evaluated temperature and radiological conditions in those areas.

Open Item: Make available for NRC staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

3.2.2 Vent Characteristics 3.2.2.1 Vent Size and Basis Order EA-13-1 09, Section 1.2.1, states that:

1.2.1 The HCVS shall have the capacity to vent the steam/energy equivalent of one (1) percent of licensed/rated thermal power (unless a lower value is justified by analyses), and be able to restore and then maintain containment pressure below the primary containment design pressure and the primary containment pressure limit.

Page 12 of the OIP states the following:

The HCVS wetwell path will be designed for venting steam/energy at a nominal capacity of 1% or greater of the current licensed thermal power (CLTP) of 1912 MWth [megawatt thermal] at a containment pressure of 53 psig [primary containment pressure limit] (PCPL). No additional Power Uprates are currently planned. This pressure is the lower of the containment design pressure (56 psig) and the PCPL value (53 psig). The nominal size of the wetwell portion of the HCVS will be 10 inches in diameter which provides adequate capacity to meet or exceed the Order [EA-13-1 09] criteria.

The DAEC OIP describes installation of a new vent sized to meet or exceed one percent or greater CLTP. This appears to be consistent with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details not available at this time include: an analysis that demonstrates sufficient HCVS capacity to vent the steam/energy equivalent of one (1) percent of licensed/rated thermal power (unless a lower value is justified), and an analysis that demonstrates that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment design pressure and the primary containment pressure limit; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit analyses demonstrating that HCVS has the capacity to vent the steam/energy equivalent of one (1) percent of licensed/rated thermal power (unless a lower value is justified), and that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment design pressure and the primary containment pressure limit.

3.2.2.2 Vent Capacity Order EA-13-109, Section 1.2.1, states that:

1.2.1 The HCVS shall have the capacity to vent the steam/energy equivalent of one (1) percent of licensed/rated thermal power (unless a lower value is justified by analyses), and be able to restore and then maintain containment pressure below the primary containment design pressure and the primary containment pressure limit.

Page 12 of the 01 P states the following:

The 1% value at DAEC assumes that the suppression pool pressure suppression capacity is sufficient to absorb the decay heat generated during the first 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.

The vent would then be able to prevent containment pressure from increasing above the containment design pressure. It was verified in the GE Safety Analysis Report for DAEC Extended Power Up rate Analysis (EPU) that the drywell and suppression pool temperatures remain below the design temperatures.

The DAEC OIP acknowledges that until decay heat is less than one percent, the suppression pool must absorb the decay heat generated and prevent containment pressure from increasing above the containment design pressure until the one percent containment vent is able to restore and maintain primary containment pressure below the primary containment design pressure and the primary containment pressure limit. DAEC references the GE Safety Analysis Report for DAEC EPU; however, DAEC does not provide information to confirm that this analysis is valid for the ELAP conditions required for Order EA-13-1 09; therefore the staff has not completed its review.

Open Item: Make available for NRC staff audit analyses demonstrating that HCVS has the capacity to vent the steam/energy equivalent of one (1) percent of licensed/rated thermal power (unless a lower value is justified), and that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment design pressure and the primary containment pressure limit.

3.2.2.3 Vent Path and Discharge Order EA-13-1 09, Sections 1.1 .4 and 1.2.2, state that:

1.1.4 The HCVS controls and indications shall be accessible and functional under a range of plant conditions, including severe accident conditions, extended loss of AC power, and inadequate containment cooling.

1.2.2 The HCVS shall discharge the effluent to a release point above main plant structures.

Page 12 of the OIP states the following:

The planned HCVS vent path at DAEC for the wetwell will utilize the existing containment penetration that supports normal venting to the Standby Gas Treatment system. It exits the Primary Containment into the Reactor Building in the Northeast Corner room. This pipe will extend through the Reactor Building to the roof.

The HCVS discharge path will be routed to a point above any adjacent structure (excludes off gas stack) This discharge point is just above the Reactor Building roof such that the release point will vent away from emergency ventilation system intake and exhaust openings, main control room location, location of HCVS portable equipment, access routes required following a ELAP and BDBEE, and emergency response facilities; however, these must be considered in conjunction with other design criteria (e.g., flow capacity) and pipe routing limitations, to the degree practical. Since pipe routing will be within the Class 1 structure of the Reactor Building until it exits the building through the roof, no tornado missile protection is expected to be required above a height of 30 feet from ground elevation. Protection from external events as defined by NEI 12-06 for the outside portions of the selected release stack or structure is warranted.

Evaluation of potential tornado missile effects on portions of HCVS located above the protected area of the Reactor Building will be performed.

The DAEC 01 P describes the routing and discharge point of the HCVS that appear consistent with the guidance found in NEI 13-02, as endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details not available at this time include: evaluations pertaining to tornado missile protection, evaluations of the environmental and radiological effects on HCVS controls and indications, and documentation of an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit evaluations of tornado missile effects on HCVS components above the protected area of the reactor building.

Open Item: Make available for NRC staff audit the descriptions of local conditions (temperature, radiation and humidity) anticipated during ELAP and severe

accident for the components (valves, instrumentation, sensors, transmitters, indicators, electronics, control devices, and etc.) required for HCVS venting including confirmation that the components are capable of performing their functions during ELAP and severe accident conditions.

Open Item: Make available for NRC staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

3.2.2.4 Power and Pneumatic Supply Sources Order EA-13-109, Sections 1.2.5 and 1.2.6, state that:

1.2.5 The HCVS shall, in addition to meeting the requirements of 1.2.4, be capable of manual operation (e.g., reach-rod with hand wheel or manual operation of pneumatic supply valves from a shielded location), which is accessible to plant operators during sustained operations.

1.2.6 The HCVS shall be capable of operating with dedicated and permanently installed equipment for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the loss of normal power or loss of normal pneumatic supplies to air operated components during an extended loss of AC power.

Page 12 of the OIP states the following:

All electrical power required for operation of HCVS components will be routed through an uninterruptible power supply with batteries sufficient for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of service.

Pneumatic power is normally provided by safety related air compressors with local accumulators at the valves. Following an ELAP event the air compressors will not be available. Existing accumulators are not s*ized for the number of venting cycles anticipated and therefore the accumulators will be upgraded or alternate supplies provided to ensure the required operating cycles for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> are maintained.

1. The HCVS flow path valves are air-operated valves (AOV) with air-to-open and spring-to shut. Opening the valves requires energizing a solenoid operated valve (SOV) and providing motive air/gas. The detailed design will provide a permanently installed power source and motive air/gas supply adequate for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The initial stored motive air/gas will allow for a minimum of eight valve operating cycles for the HCVS valves for the first 24-hours.

2. An assessment of temperature and radiological conditions will be performed to ensure that operating personnel can safely access and operate controls at the Remote Operating Station [ROS] based on time constraints listed in Attachment 7 [of the OIP] (Action Item 2).

3. All permanently installed HCVS equipment, including any connections required to supplement the HCVS operation during an ELAP (i.e., electric power, N2/air) will be located in areas reasonably protected from defined hazards listed in Part 1 of this report.

4. All valves required to open the flow path or valves that require manual operation to be closed to prevent diversion or cross-flow into other systems are designed for remote manual operation following a ELAP, such that the primary means of valve manipulation does not rely on use of a hand wheel, reach-rod or similar means that requires close proximity to the valve (reference FAQ HCVS-03). Any supplemental connections will be pre-engineered to minimize manpower resources and address environmental concerns. Required portable equipment will be reasonably protected from screened in hazards listed in Part 1 [of the OIP].

5. Access to the locations described above will not require temporary ladders or scaffolding.

6. Following the initial 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period, additional motive force will be supplied from compressed gas bottles that will be connected near the ROS in the control building essential switchgear room such that radiological impacts are minimized.

The DAEC OIP contains system feature descriptions that appear to make the system reliable consistent with the guidance found in NEI 13-02, as endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details not available at this time include: the final sizing evaluation for HCVS pneumatic supply, the final sizing for HCVS battery/battery charger including documentation of incorporating HCVS electrical sources into the FLEX DG loading calculations, and documentation of an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit the final sizing evaluation for pneumatic N2 supply.

Open Item: Make available for NRC staff audit the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation.

Open Item: Make available for NRC staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

3.2.2.5 Location of Control Panels Order EA-13-1 09, Sections 1.1.1, 1.1.2, 1.1.3, 1.1.4, 1.2.4, and 1.2.5, state that:

1.1.1 The HCVS shall be designed to minimize the reliance on operator actions.

1.1.2 The HCVS shall be designed to minimize plant operators' exposure to occupational hazards, such as extreme heat stress, while operating the HCVS system.

1.1 .3 The HCVS shall also be designed to account for radiological conditions that would impede personnel actions needed for event response.

1.1.4 The HCVS controls and indications shall be accessible and functional under a range of plant conditions, including severe accident conditions, extended loss of AC power, and inadequate containment cooling.

1.2.4 The HCVS shall be designed to be manually operated during sustained operations from a control panel located in the main control room or a remote but readily accessible location.

1.2.5 The HCVS shall, in addition to meeting the requirements of 1.2.4, be capable of manual operation (e.g., reach-rod with hand wheel or manual operation of pneumatic supply valves from a shielded location), which is accessible to plant operators during sustained operations.

Page 13 of the OIP states the following:

The HCVS design allows initiating and then operating and monitoring the HCVS from the Main Control Room (MCR). A remote control station will be established in the 1A4 essential Switchgear Room, but use of this remote control station is not required in the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The MCR and the essential switchgear location are protected from adverse natural phenomena and are the normal control points for Plant Emergency Response actions.

The DAEC OIP describes HCVS control locations that appear to be consistent with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details not available at this time include: documentation that demonstrates adequate communication between remote HCVS operation locations and HCVS operational decision makers, evaluations of the environmental and radiological effects on HCVS controls and indications, and an evaluation of environmental and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit documentation that demonstrates adequate communication between the remote HCVS operation locations and HCVS decision makers during ELAP and severe accident conditions.

Open Item: Make available for NRC staff audit the descriptions of local conditions (temperature, radiation and humidity) anticipated during ELAP and severe accident for the components (valves, instrumentation, sensors, transmitters, indicators, electronics, control devices, and etc.) required for HCVS venting including confirmation that the components are capable of performing their functions during ELAP and severe accident conditions.

Open Item: Make available for NRC staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

3.2.2.6 Hydrogen Order EA-13-1 09, Sections 1.2.1 0, 1.2.11, and 1.2.12, state that:

1.2.1 0 The HCVS shall be designed to withstand and remain functional during severe accident conditions, including containment pressure, temperature, and radiation while venting steam, hydrogen, and other non-condensable gases and aerosols. The design is not required to exceed the current capability of the limiting containment components.

1.2.11 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.

1.2.12 The HCVS shall be designed to minimize the potential for hydrogen gas migration and ingress into the reactor building or other buildings.

Page 13 of the OIP states the following:

As is required by EA-13-1 09, Section 1.2.11, the HCVS must be designed such that it is able to either provide assurance that oxygen cannot enter and mix with flammable gas in the HCVS (so as to form a combustible gas mixture), or it must be able to accommodate the dynamic loading resulting from a combustible gas detonation. Several configurations are available which will support the former (e.g., purge, mechanical isolation from outside air, etc.) or the latter (design of potentially affected portions of the system to withstand a detonation relative to pipe stress and support structures).

An evaluation will be performed of the system design for hydrogen/carbon monoxide control measures (See Attachment ?[of the OIP] Open Item 4).

A description of the final design for hydrogen control is not available at this time including a description of the final design of the HCVS to address hydrogen detonation and deflagration (licensee identified) and a description of the strategies for hydrogen control that minimizes the

potential for hydrogen gas migration and ingress into the reactor building or other buildings; therefore, the staff has not completed its review.

Open Item: Provide a description of the final design of the HCVS to address hydrogen detonation and deflagration.

Open Item: Provide a description of the strategies for hydrogen control that minimizes the potential for hydrogen gas migration and ingress into the reactor building or other buildings.

3.2.2.7 Unintended Cross Flow of Vented Fluids Order EA-13-1 09, Sections 1.2.3 and 1.2.12, state that:

1.2.3 The HCVS shall include design features to minimize unintended cross flow of vented fluids within a unit and between units on the site.

1.2.12 The HCVS shall be designed to minimize the potential for hydrogen gas migration and ingress into the reactor building or other buildings.

Page 13 of the OIP states the following:

The HCVS will use the Containment Purge System containment isolation valves (CV-4300, CV-4301 and CV-4309) for containment isolation along with hardened vent valve CV-4357. These containment isolation valves are AOVs and they are air-to-open and spring-to-shut. CV-4300 and CV-4357 must be open to establish the vent path and CV-4301 must be closed to isolate the purge path from unintended flow when using the HCVS. An SOV must be energized to allow the motive air to open the valve. Although CV-4300 is shared between the Containment Purge System and the HCVS, separate solenoid power control circuits will be provided for each function. Specifically:

• The Containment Purge System control circuit is AC powered and will be used during normal operating modes.

• DC [direct current] powered control circuits supply the solenoids that control opening of CV-4300 and CV-4357 when using the HCVS.

• Loss of power or primary containment isolation signals ensure CV-4301 is closed under conditions associated with HCVS use.

The diagram provided in attachment 3 of the OIP sketch 2 does not contain sufficient detail to confirm the description in the OIP; therefore the staff has not completed its review.

Open Item: Make available for NRC staff audit additional detail on the design features that minimize unintended cross flow of vented fluids within a unit, including a one line diagram containing sufficient detail to confirm the description in the OIP.

3.2.2.8 Prevention of Inadvertent Actuation Order EA-13-1 09, Section 1.2. 7, states that:

1.2. 7 The HCVS shall include means to prevent inadvertent actuation.

Page 14 of the 01 P states the following:

For design bases accidents and transients, containment cooling is available and EOP [emergency operating procedure] guidance would not require use of the HCVS. In addition, the HCVS will be designed to provide features to prevent inadvertent actuation due to a design error, equipment malfunction, or operator error such that any credited containment accident pressure (CAP) that would provide net positive suction head to the emergency core cooling system (ECCS) pumps will be available (inclusive of a design basis loss-of coolant accident (DBLOCA)). DAEC credits containment over pressure for DBLOCA as described in UFSAR [updated final safety analysis report] Section 5.4 and shown in UFSAR figures 5.4-15 sheet 1 and 5.4-15 sheet 2. However, for conditions assumed by Order EA-13-1 09 the ECCS pumps will not have normal power available because of the starting boundary conditions of an ELAP.

The features that prevent inadvertent actuation are two PCIVs [primary containment isolation valves] in series with key lock switches. The current plant design includes a rupture disc set at approximately 50 PSIG. It is anticipated that final design of the HCVS system will eliminate this rupture disc to simplify venting operations provided any leakage that bypasses secondary containment for design bases events is confirmed to be acceptable.

• Confirm secondary containment bypass leakage is acceptable without an installed rupture disk or retain an appropriate disk (See Attachment 7 [of the OIP], Open Item 1).

The DAEC OIP provides a description of methods to prevent inadvertent HCVS initiation that includes: key lock switches, valves in series powered from separate power supplies and procedural guidance. This appears to be consistent with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Specific details on rupture disc design are not available at this time; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit, documentation of licensee confirmation that secondary containment leakage is acceptable without an installed rupture disk or that an appropriate rupture disk, including procedures for rupture during HCVS operation, is included in the HCVS design.

3.2.2.9 Component Qualifications Order EA-13-1 09, Section 2.1, states that:

2.1 The HCVS vent path up to and including the second containment isolation barrier shall be designed consistent with the design basis of the plant.

Items in this path include piping, piping supports, containment isolation valves, containment isolation valve actuators and containment isolation valve position indication components.

Page 14 of the OIP states the following:

The HCVS components downstream of the second containment isolation valve and components that interface with the HCVS will be routed in seismically qualified structures. HCVS components that directly interface with the primary containment pressure boundary will be considered safety related, as the existing system is safety related. The containment system limits the leakage or release of radioactive materials to the environment to prevent offsite exposures from exceeding the guidelines of 10 CFR 50.67. During normal or design basis operations, this means serving as a pressure boundary to prevent release of radioactive material.

Likewise, any electrical or controls component which interfaces with Class 1E power sources will be considered safety related, up to and including appropriate isolation devices such as fuses or breakers, as their failure could adversely impact containment isolation and/or a safety-related power source. The remaining components will be considered Augmented Quality. Newly installed piping and valves will be seismically evaluated to handle the forces associated with the seismic margin earthquake (SME) back to their isolation boundaries.

Electrical and controls components will be seismically rugged and will include the ability to handle harsh environmental conditions, as needed (although they will not be considered part of the site Environmental Qualification (EQ) program).

HCVS instrumentation performance (e.g., accuracy and precision) need not exceed that of similar plant installed equipment. Additionally, radiation monitoring equipment accuracy and range will be sufficient to confirm flow of radionuclides through the HCVS but will not directly quantify effluents.

The HCVS instruments, including valve position indication, process instrumentation, radiation monitoring, and support system monitoring, will be qualified by using one or more of the three methods described in the ISG [JLD-ISG-2013-02], which includes:

1. Purchase of instruments and supporting components with known operating principles from manufacturers with commercial quality assurance programs (e.g., 1809001) where the procurement specifications include the applicable seismic requirements, design requirements, and applicable testing.

2. Demonstration of seismic reliability via methods that predict performance described in IEEE 344-2004

3. Demonstration that instrumentation is substantially similar to the design of instrumentation previously qualified.

Instrument Qualification Method*

HCVS Process Temperature IS09001 I IEEE 344-1975 I Demonstration HCVS Process Pressure IS09001 I IEEE 344-1975 I Demonstration HCVS Process Radiation Monitor IS09001 I IEEE 344-1975 I Demonstration HCVS Process Valve Position IS09001 I IEEE 344-1975 I Demonstration HCVS Pneumatic Supply Pressure IS09001 I IEEE 344-1975 I Demonstration HCVS Electrical Power Supply Availability IS09001 I IEEE 344-1975 I Demonstration

• The specific qualification method(s) used for each requ1red HCVS instrument will be reported in future 6 month status reports.

The DAEC OIP deviates from the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09 by substituting IEEE 344-1975 for IEEE 344-2004 when qualifying instrumentation and inconsistently referencing both IEEE 344-1975 and IEEE 344-2004 in different places. As such, DAEC's OIP is unclear as to which standard the licensee intends to use. Specific HCVS component qualification details that take into account local conditions (temperature, radiation and humidity) confirming that HCVS components are capable of performing their functions is not available at this time. Further, DAEC has not confirmed that the containment isolation valves, relied upon for the HCVS, will open under the maximum expected differential pressure during BDBEE and severe accident wetwell venting; therefore, the staff has not completed its review.

Open Item: Provide a justification for deviating from the instrumentation seismic qualification guidance specified in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09.

Open Item: Make available for NRC staff audit the descriptions of local conditions (temperature, radiation and humidity) anticipated during ELAP and severe accident for the components (valves, instrumentation, sensors, transmitters, indicators, electronics, control devices, and etc.) required for HCVS venting including confirmation that the components are capable of performing their functions during ELAP and severe accident conditions.

Open Item: Make available for NRC staff audit documentation of an evaluation verifying the existing containment isolation valves, relied upon for the HCVS, will open under the maximum expected differential pressure during BDBEE and severe accident wetwell venting.

3.2.2.1 0 Monitoring of HCVS Order EA-13-1 09, Sections 1.1.4, 1.2.8, and 1.2.9, state that:

1.1.4 The HCVS controls and indications shall be accessible and functional under a range of plant conditions, including severe accident conditions, extended loss of AC power, and inadequate containment cooling.

1.2.8 The HCVS shall include means to monitor the status of the vent system (e.g., valve position indication) from the control panel required by 1.2.4.

The monitoring system shall be designed for sustained operation during an extended loss of AC power.

1.2.9 The HCVS shall include a means to monitor the effluent discharge for radioactivity that may be released from operation of the HCVS. The monitoring system shall provide indication from the control panel required by 1.2.4 and shall be designed for sustained operation during an extended loss of AC power.

Page 15 of the OIP states the following:

The DAEC wetwell HCVS will be capable of being manually operated during sustained operations from a control panel located in the main control room (MCR) and will meet the requirements of Order element 1.2.4. The MCR is a readily accessible location with no further evaluation required. Control Room dose associated with HCVS operation conforms to GDC 19/Aiternative Source Term (AST).

Additionally, to meet the intent for a secondary control location of section 1.2.5 of the Order, a readily accessible Remote Operating Station (ROS) will also be incorporated into the HCVS design as described in NEI 13-02 section 4.2.2.1.2.1.

The controls and indications at the ROS location will be accessible and functional under a range of plant conditions, including severe accident conditions with due consideration to source term and dose impact on operator exposure, extended loss of AC power (ELAP), and inadequate containment cooling. An evaluation will be performed to determine accessibility to the location, habitability, staffing sufficiency, and communication capability with vent-use decision makers.

The wetwell HCVS will include means to monitor the status of the vent system in both the MCR and the ROS. Included in the current design of the hardened vent (HV) are control switches in the MCR with valve position indication. The existing HV controls currently meet the environmental and seismic requirements of the Order for the plant severe accident and will be upgraded to address ELAP. The ability to open/close these valves multiple times during the event's first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> will be provided by air accumulator tanks and the HCVS uninterruptible power supply. Beyond the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, the ability to open these valves will be ensured with replaceable compressed gas bottles and FLEX generators.

Prevention of inadvertent operation of HCVS from the ROS will be accomplished by other positive physical control (e.g., locked valve separated from air tank to not inadvertently pressurize).

The wetwell HCVS will include indications for vent pipe temperature and system effluent radiation levels in the MCR. Other important information on the status of supporting systems, such as power source status and pneumatic supply pressure, will also be included in the design and located to support HCVS operation. The wetwell HCVS will include existing containment pressure and wetwell level indication in the MCR to monitor vent operation. This monitoring instrumentation provides the indication from the MCR as per Requirement 1.2.4 and will be designed for sustained operation during an ELAP event consistent with FLEX key parameter indication.

The DAEC OIP provides a description of HCVS monitoring and control that appears to be consistent with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details not available at this time include: descriptions of all instrumentation and controls (existing and planned) including qualification methods, evaluations of the environmental and radiological effects on HCVS controls and indications, and an evaluation of environmental and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit descriptions of all instrumentation and controls (existing and planned) necessary to implement this order including qualification methods.

Open Item: Make available for NRC staff audit the descriptions of local conditions (temperature, radiation and humidity) anticipated during ELAP and severe accident for the components (valves, instrumentation, sensors, transmitters, indicators, electronics, control devices, and etc.) required for HCVS venting including confirmation that the components are capable of performing their functions during ELAP and severe accident conditions.

Open Item: Make available for NRC staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

3.2.2.11 Component Reliable and Rugged Performance Order EA-13-1 09, Section 2 .2, states that:

2.2 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.

Page 16 of the 01 P states the following:

The HCVS downstream of the second containment isolation valve, including piping and supports, electrical power supply, valve actuator pneumatic supply, and instrumentation (local and remote) components, will be designed/analyzed to conform to the requirements consistent with the applicable design codes (e.g.,

Non-safety, Cat 1, SS and 300# ASME or 831.1, NEMA 4, etc.) for the plant and to ensure functionality following a design basis earthquake.

Additional modifications required to meet the Order will be reliably functional at the temperature, pressure, and radiation levels consistent with the vent pipe conditions for sustained operations. The instrumentation/power supplies/cables/connections (components) will be qualified for temperature, pressure, radiation level, total integrated dose radiation for the Effluent Vent Pipe.

Conduit design will be installed to Seismic Class 1 criteria. Conduit will be located inside a seismically qualified structure. Augmented quality requirements, will be applied to the components installed in response to this Order.

If the instruments are purchased as commercial-grade equipment, they will be qualified to operate under severe accident environment as required by NRC Order EA-13-109 and the guidance of NEI 13-02. These qualifications will be bounding conditions for DAEC.

For the instruments required after a potential seismic event, the following methods will be used to verify that the design and installation is reliable I rugged and thus capable of ensuring HCVS functionality following a seismic event.

Applicable instruments are rated by the manufacturer (or otherwise tested) for seismic impact at levels commensurate with those of postulated severe accident event conditions in the area of instrument component use using one or more of the following methods:

• demonstration of seismic motion will be consistent with that of existing design basis loads at the installed location;

• substantial history of operational reliability in environments with significant vibration with a design envelope inclusive of the effects of seismic motion imparted to the instruments proposed at the location;

• adequacy of seismic design and installation is demonstrated based on the guidance in Sections 7, 8, 9, and 10 of IEEE Standard 344-2004, IEEE Recommended Practice for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations, (Reference 27 of the DAEC OIP) or a substantially similar industrial standard;

• demonstration that proposed devices are substantially similar in design to models that have been previously tested for seismic effects in excess of

the plant design basis at the location where the instrument is to be installed (g-levels and frequency ranges); or

• Seismic qualification using seismic motion consistent with that of existing design basis loading at the installation location.

The DAEC 01 P provides descriptions for component reliable and rugged performance that appear to be consistent with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09.

3.2.3 Beyond-Design-Basis External Event Venting 3.2.3.1 First 24-Hour Coping Order EA-13-1 09, Section 1.2.6, states that:

1.2.6 The HCVS shall be capable of operating with dedicated and permanently installed equipment for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the loss of normal power or loss of normal pneumatic supplies to air operated components during an extended loss of AC power.

Page 18 of the OIP states the following:

The operation of the HCVS will be designed to minimize reliance on operator actions for response to an ELAP and severe accident events. Immediate operator actions will be completed by qualified plant personnel from either the MCR or the HCVS ROS using remote-manual actions. The operator actions required to open a vent path are as described in Table 2-1 [of the OIP].

Remote-manual is defined in this report as a non-automatic power operation of a component and does not require the operator to be at or in close proximity to the component. No other operator actions are required to initiate venting under the guiding procedural protocol.

The HCVS will be designed to allow initiation, control, and monitoring of venting from the Relay Room. This location minimizes plant operators' exposure to adverse temperature and significant radiological conditions and is protected from hazards assumed in Part 1 of the DAEC OIP.

Permanently installed electrical power and motive gas capability will be available to support operation and monitoring of the HCVS for 24-hours.

System control:

Active: Control valves and/or PCIVs are operated in accordance with EOPs/SAGs [Severe Accident Guidelines] to control containment pressure. The HCVS will be designed for eight open/close cycles under ELAP conditions over the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following an ELAP. Controlled venting will be permitted in the revised EPGs and associated implementing EOPs. The containment isolation signal can be over ridden using an existing hand switch in the main control room HS-4300A, "CV-4300 HARD PIPE VENT ALT PWRIPCIS".

Passive: Inadvertent actuation protection is provided by redundant valves with key lock switches located in the Main Control Room and as directed by applicable procedures.

The DAEC OIP describes a first 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> BDBEE coping strategy that appears to be in accordance with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details not available at this time include: the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation, and the final sizing evaluation for pneumatic N2 supply; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation.

Open Item: Make available for NRC staff audit the final sizing evaluation for pneumatic N2 supply.

3.2.3.2 Greater Than 24-Hour Coping Order EA-13-1 09, Section 1.2.4, states that:

1.2.4 The HCVS shall be designed to be manually operated during sustained operations from a control panel located in the main control room or a remote but readily accessible location.

Page 18 of the OIP states the following:

After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, available personnel will be able to connect supplemental motive gas to the HCVS. Connections for supplementing electrical power and motive gas required for HCVS will be located in accessible areas with reasonable protection per NEI 12-06 that minimize personnel exposure to adverse conditions for HCVS initiation and operation. Connections will be pre-engineered quick disconnects to minimize manpower resources. Electrical Power will be supplemented consistent with NRC Order EA-12-049.

These actions provide long term support for HCVS operation for the period beyond 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to 7 days (sustained operation time period) because on-site and

off-site personnel and resources will have access to the unit to provide needed action and supplies.

The DAEC OIP describes a greater than 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> BDBEE coping strategy that appears to be in accordance with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details not available at this time include: the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation, and the final sizing evaluation for pneumatic N2 supply; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation.

Open Item: Make available for NRC staff audit the final sizing evaluation for pneumatic N2 supply.

3.2.4 Severe Accident Event Venting 3.2.4.1 First 24 Hour Coping Order EA-13-109, Section 1.2.6, states that:

1.2.6 The HCVS shall be capable of operating with dedicated and permanently installed equipment for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the loss of normal power or loss of normal pneumatic supplies to air operated components during an extended loss of AC power.

Page 21 of the OIP states the following:

The operation of the HCVS will be designed to minimize reliance on operator actions for response to an ELAP and severe accident events. Severe accident event assumes that specific core cooling actions from the FLEX strategies identified in the response to Order EA-12-049 were not successfully initiated.

Access to the reactor building will be restricted as determined by Operators in the Main Control Room (MCR) or at the HCVS Remote Operating Station (ROS) and will include remote-manual actions. The operator actions required to open a vent path were previously listed in the BDBEE Venting section of this report [the DAEC OIP] (Table 2-1[of the OIP]).

Permanently installed power and motive air/gas will be available to support operation and monitoring of the HCVS for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. ~pecifics are the same as for BEBEE Venting.

System control:

Active: same as for BEBEE Venting Passive: same as for BEBEE Venting; If a rupture disk is retained in the final design it will automatically burst prior to exceeding containment design pressures.

The DAEC OIP describes a first 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> severe accident coping strategy that appears to be in accordance with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details not available at this time include: the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation, the final sizing evaluation for pneumatic N2 supply, and an evaluation of environmental and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation.

Open Item: Make available for NRC staff audit the final sizing evaluation for pneumatic N2 supply.

Open Item: Make available for NRC staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

3.2.4.2 Greater Than 24 Hour Coping Order EA-13-1 09, Sections 1.2.4 and 1.2.8, state that:

1.2.4 The HCVS shall be designed to be manually operated during sustained operations from a control panel located in the main control room or a remote but readily accessible location.

1.2.8 The HCVS shall include means to monitor the status of the vent system (e.g., valve position indication) from the control panel required by 1.2.4.

The monitoring system shall be designed for sustained operation during an extended loss of AC power.

Page 21 of the OIP states the following:

Specifics are the same as for BDBEE Venting except the location and refueling actions for the FLEX DG and replacement compressed gas bottles will be evaluated for SA environmental conditions resulting from the proposed damaged Reactor Core and resultant HCVS vent pathway.

Perform SA Evaluation for FLEX DG and replacement compressed gas bottles use for post 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> actions (See Attachment 7 [of the OIP], Open Item 2).

These actions provide long term support for HCVS operation for the period beyond 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to 7 days (sustained operation time period) because on-site and off-site personnel and resources will have access to the unit to provide needed action and supplies.

The DAEC OIP describes greater than 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> severe accident coping strategy that appears to be in accordance with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details not available at this time include: the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation, the final sizing evaluation for pneumatic N2 supply, and an evaluation of environmental and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation.

Open Item: Make available for NRC staff audit the final sizing evaluation for pneumatic N2 supply.

Open Item: Make available for NRC staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

3.2.5 Support Equipment Functions 3.2.5.1 BDBEE Order EA-13-1 09, Sections 1.2.8 and 1.2.9, state that:

1.2.8 The HCVS shall include means to monitor the status of the vent system (e.g., valve position indication) from the control panel required by 1.2.4.

The monitoring system shall be designed for sustained operation during an extended loss of AC power.

1.2.9 The HCVS shall include a means to monitor the effluent discharge for radioactivity that may be released from operation of the HCVS. The monitoring system shall provide indication from the control panel required by 1.2.4 and shall be designed for sustained operation during an extended loss of AC power.

Page 23 of the OIP states the following:

Containment integrity is initially maintained by permanently installed equipment.

All containment venting functions will be performed from the MCR or ROS.

Venting will require support from a newly installed uninterruptable power supply.

Before the dedicated UPS is depleted, portable FLEX diesel generators, as detailed in the response to Order EA- 12-049, will be credited to charge the UPS.

Improved pneumatic accumulator tanks with back-up portable compressed gas bottles will provide sufficient motive force for all HCVS valve operation and will provide for multiple operations of CV-4300 or CV-4357 vent valves.

The DAEC OIP describes BDBEE supporting equipment functions that appear to be in accordance with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details not available at this time include: the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation, and the final sizing evaluation for pneumatic N2 supply; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation.

Open Item: Make available for NRC staff audit the final sizing evaluation for pneumatic N2 supply.

3.2.5.2 Severe Accident Venting Order EA-13-1 09, Sections 1.2.8 and 1.2.9, state that:

1.2.8 The HCVS shall include means to monitor the status of the vent system (e.g., valve position indication) from the control panel required by 1.2.4.

The monitoring system shall be designed for sustained operation during an extended loss of AC power.

1.2.9 The HCVS shall include a means to monitor the effluent discharge for radioactivity that may be released from operation of the HCVS. The monitoring system shall provide indication from the control panel required by 1.2.4 and shall be designed for sustained operation during an extended loss of AC power.

Page 23 of the OIP states the following:

The same support functions that are used in the BDBEE scenario would be used for severe accident venting. To ensure power for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, a dedicated HCVS uninterruptable power supply will be available to feed HCVS loads. At 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, power will be backed up by FLEX generators evaluated for SA accessibility.

Hydrogen mitigation strategies will be evaluated (See Attachment 7 [of the OIP]).

Compressed gas bottles will be available to tie-in supplemental pneumatic sources.

The DAEC OIP describes support equipment functions for severe accident venting that appear to be in accordance with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09.

Design details not available at this time include: the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation, the final sizing evaluation for pneumatic N2 supply, and an evaluation of environmental and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation.

Open Item: Make available for NRC staff audit the final sizing evaluation for pneumatic N2 supply.

Open Item: Make available for NRC staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

3.2.6 Venting Portable Equipment Deployment Order EA-13-1 09, Section 3.1 , states that:

3.1 The licensee shall develop, implement, and maintain procedures necessary for the safe operation of the HCVS. Procedures shall be established for system operations when normal and backup power is available, and during an extended loss of AC power.

Page 25 of the OIP states the following:

Deployment pathways for compliance with Order EA-12-049 are acceptable without further evaluation needed except in areas around the Reactor Building or in the vicinity of the HCVS piping. Deployment in the areas around the Reactor Building or in the vicinity of the HCVS piping will allow access, operation and replenishment of consumables with the consideration that there is potential Reactor Core Damage and HCVS operation.

The DAEC OIP describes venting portable equipment deployment functions that appear to be in accordance with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. Design details are not available at this time. Specifically, an evaluation of environmental and radiological conditions of pathways around the reactor building or in the vicinity of the HCVS piping to ensure that operating personnel can safely access and operate controls and support equipment are not available at this time; therefore, the staff has not completed its review.

Open Item: Make available for NRC staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

Summary, Section 3.2:

The licensee's approach to Boundary Conditions for Wet Well Vent, if implemented as described in Section 3.2, and assuming acceptable resolution of any open items identified here or as a result of licensee alterations to their proposed plans, appears to be consistent with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09.

3.3 BOUNDARY CONDITIONS FOR DRY WELL VENT Summary, Section 3.3:

Dry Well Vent will be evaluated during Phase 2 of Order EA-13-1 09. The ISG for Phase 2 will be provided by April 30, 2015. Licensees will submit an updated OIP to address Phase 2 of Order EA-13-109 by December 31, 2015.

3.4 PROGRAMMATIC CONTROLS, TRAINING, DRILLS AND MAINTENANCE 3.4.1 Programmatic Controls Order EA-13-1 09, Sections 3.1 and 3.2, state that:

3.1 The licensee shall develop, implement, and maintain procedures necessary for the safe operation of the HCVS. Procedures shall be established for system operations when normal and backup power is available, and during an extended loss of AC power.

3.2 The licensee shall train appropriate personnel in the use of the HCVS.

The training curricula shall include system operations when normal and backup power is available, and during an extended loss of AC power.

Page 28 of the OIP states the following:

Program Controls:

The HCVS venting actions will include:

• Site procedures and programs are being developed in accordance with NEI 13-02 to address use and storage of portable equipment relative to the Severe Accident defined in NRC Order EA-13-109 and the hazards applicable to the site per Section 3.1 of DAEC OIP.

• Routes for transporting portable equipment from storage location(s) to deployment areas will be developed as the response details are

identified and finalized. The identified paths and deployment areas will be accessible during all modes of operation and during Severe Accidents.

Procedures:

Procedures will be established for system operations when normal and backup power is available, and during ELAP conditions.

The HCVS procedures will be developed and implemented following the plant's process for initiating or revising procedures and contain the following details:

• appropriate conditions and criteria for use of the HCVS

• when and how to place the HCVS in operation,

• the location of system components,

• instrumentation available,

• normal and backup power supplies,

• directions for sustained operation, including the storage location of portable equipment,

• training on operating the portable equipment, and

• testing of portable equipment For design bases events, DAEC credits containment overpressure to support NPSH [net positive suction head] for AC powered, emergency core cooling system pumps as shown in UFSAR figures 5.4-15 sheet 1 and 5.4-15 sheet 2.

The AC powered pumps are not available during an ELAP. Procedures for operation of the containment vent, will address potential impacts on NPSH.

Provisions for out-of-service requirements will be established for the HCVS and compensatory measures. The following provisions will be documented in site administrative controls:

• The provisions for out-of-service requirements for HCVS are applicable in Modes 1, 2 and 3

• If for up to 90 consecutive days, the primary or alternate means of HCVS operation are non-functional, no compensatory actions are necessary.

• If for up to 30 days, the primary and alternate means of HCVS operation are non-functional, no compensatory actions are necessary.

• If the out of service times exceed 30 or 90 days as described above, the following actions will be performed:

o The condition will entered into the corrective action system, o The HCVS availability will be restored in a manner consistent with plant procedures,

o A cause assessment will be performed to prevent future unavailability for similar causes.

o Actions will be initiated to implement appropriate compensatory actions.

The DAEC OIP describes programmatic controls that appear to be consistent with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. NRC staff determined that procedure development appears to be in accordance with existing industry protocols. The provisions for out-of-service requirements appear to reflect consideration of the probability of an ELAP requiring severe accident venting and the consequences of a failure to vent under such conditions.

3.4.2 Training Order EA-13-1 09, Section 3.2, states that:

3.2 The licensee shall train appropriate personnel in the use of the HCVS.

The training curricula shall include system operations when normal and backup power is available, and during an extended loss of AC power.

Page 29 of the OIP states the following:

Personnel expected to perform direct execution of the HVCS will receive necessary training in the use of plant procedures for system operations when normal and backup power is available and during ELAP conditions. The training will be refreshed on a periodic basis and as any changes occur to the HCVS.

Training content and frequency will be established using the Systematic Approach to Training (SAT) process.

In addition, (Reference NEI 12-06) all personnel on-site will be available to supplement trained personnel [applies only to FLEX].

The DAEC OIP describes HCVS training requirements that appear to be in accordance with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09. The systematic approach to training process has been accepted by the NRC as appropriate for developing training for nuclear plant personnel.

3.4.3 Drills Order EA-13-1 09, Section 3.1 , states that:

3.1 The licensee shall develop, implement, and maintain procedures necessary for the safe operation of the HCVS. Procedures shall be established for system operations when normal and backup power is available, and during an extended loss of AC power.

Page 29 of the OIP states the following:

The site will utilize the guidance provided in NEI 13-06 and 14-01 for guidance related to drills, tabletops, or exercises for HCVS operation. In addition, the site will integrate these requirements with compliance to any rulemaking resulting from the NTTF Recommendations 8 and 9.

The DAEC OIP describes an approach to drills to be in accordance with NEI 13-06, "Enhancements to Emergency Response Capabilities for Beyond Design Basis Accidents" and Events and NEI 14-01, "Emergency Response Procedures and Guidelines for Extreme Events and Severe Accidents." This approach appears to be in accordance with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09.

3.4.4 Maintenance Order EA-13-1 09, Section 1.2.13, states that:

1.2.13 The HCVS shall include features and provisions for the operation, testing, inspection and maintenance adequate to ensure that reliable function and capability are maintained.

Page 30 of the OIP states the following:

The site will utilize the standard EPRI [Electric Power Research Institute] industry PM process (similar to the Preventive Maintenance Basis Database) for establishing the maintenance calibration and testing actions for HCVS components. The control program will include maintenance guidance, testing procedures and frequencies established based on type of equipment and considerations made within the EPRI guidelines.

DAEC will implement the following operation, testing and inspection requirements for the HCVS to ensure reliable operation of the system.

T a bl e 4- 1: [0 f th e 01 P] T est"1ng an dl nspec1on t" Re_gUiremen s Description Frequency Cycle the HCVS valves and the interfacing Once per operating cycle system valves not used to maintain containment integrity during operations.

Perform visual inspections and a walk Once per operating cycle down of HCVS components.

Test and calibrate the HCVS radiation Once per operating cycle monitors.

Leak test the HCVS. (1) Prior to first declaring the system functional; (2) Once every three operating cycles thereafter; and (3) After restoration of any breach of system boundary within the buildings Validate the HCVS operating procedures Once per every other operating cycle by conducting an open/close test of the HCVS control logic from its control panel and ensuring that all interfacing system valves move to their proper (intended) positions.

The DAEC OIP describes an approach to maintenance that appears to be in accordance with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09.

Summary, Section 3.4:

The licensee's approach to Programmatic Controls Training, Drills and Maintenance, if implemented as described in Section 3.4, and assuming acceptable resolution of any open items identified here or as a result of licensee alterations to their proposed plans, appears to be consistent with the guidance found in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09.

4.0 OPEN ITEMS This section contains a summary of the open items identified to date as part of the technical evaluation. Open items, whether NRC or licensee identified, are topics for which there is insufficient information to fully resolve the issue, for which the NRC staff requires clarification to ensure the issue is on a path to resolution, or for which the actions to resolve the issue are not yet complete. The intent behind designating an issue as an open item is to highlight items that the staff intends to review further. The NRC staff has reviewed the licensee OIP for consistency with NRC policy and technical accuracy. NRC and licensee identified open items have been identified in Section 3.0 and are listed in the table below.

L.IS t 0 f 01pen 1't ems Open Item Action Comment

1. Make available for NRC staff audit documentation of licensee Section 3.1.2 confirmation that secondary containment leakage is acceptable Section 3.2.2.8 without an installed rupture disk or that an appropriate rupture disk, including procedures for rupture during HCVS operation, is included in the HCVS design.

2. Make available for NRC staff audit analyses demonstrating that Section 3.2.2.1 HCVS has the capacity to vent the steam/energy equivalent of Section 3.2.2.2 one (1) percent of licensed/rated thermal power (unless a lower value is justified), and that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment design pressure and the primary containment pressure limit.

3. Make available for NRC staff audit evaluations of tornado Section 3.2.2.3 missile effects on HCVS components above the protected area of the reactor building.

4. Make available for NRC staff audit additional detail on the Section 3.2.2. 7 design features that minimize unintended cross flow of vented fluids within a unit, including a one line diagram containing sufficient detail to confirm the description in the OIP.

5. Provide a description of the final design of the HCVS to address Section 3.2.2.6 hydrogen detonation and deflagration.

6. Provide a description of the strategies for hydrogen control that Section 3.2.2.6 minimizes the potential for hydrogen gas migration and ingress into the reactor building or other buildings.

7. Make available for NRC staff audit documentation that Section 3.2.2.5 demonstrates adequate communication between the remote HCVS operation locations and HCVS decision makers during ELAP and severe accident conditions.

8. Make available for NRC staff audit an evaluation of temperature Section 3.2.1 and radiological conditions to ensure that operating personnel Section 3.2.2.3 can safely access and operate controls and support equipment. Section 3.2.2.4 Section 3.2.2.5 Section 3.2.2.1 0 Section 3.2.4.1 Section 3.2.4.2 Section 3.2.5.2 Section 3.2.6

9. Make available for NRC staff audit the final sizing evaluation for Section 3.2.2.4 HCVS batteries/battery charger including incorporation into Section 3.2.3.1 FLEX DG loading calculation. Section 3.2.3.2 Section 3.2.4.1 Section 3.2.4.2 Section 3.2.5.1 Section 3.2.5.2

10. Make available for NRC staff audit the final sizing evaluation for Section 3.2.2.4 pneumatic N2 supply. Section 3.2.3.1 Section 3.2.3.2 Section 3.2.4.1 Section 3.2.4.2 Section 3.2.5.1 Section 3.2.5.2

11. Make available for NRC staff audit documentation of an Section 3.2.2.9 evaluation verifying the existing containment isolation valves, relied upon for the HCVS, will open under the maximum expected differential pressure during BDBEE and severe accident wetwell venting.

12. Make available for NRC staff audit descriptions of all Section 3.2.2.1 0 instrumentation and controls (existing and planned) necessary to implement this order including qualification methods.

13. Make available for NRC staff audit the descriptions of local Section 3.2.2.3 conditions (temperature, radiation and humidity) anticipated Section 3.2.2.5 during ELAP and severe accident for the components (valves, Section 3.2.2.9 instrumentation, sensors, transmitters, indicators, electronics, Section 3.2.2.1 0 control devices, and etc.) required for HCVS venting including confirmation that the components are capable of performing their functions during ELAP and severe accident conditions.

14. Provide a justification for deviating from the instrumentation Section 3.2.2.9 seismic qualification guidance specified in NEI 13-02, endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing applicable requirements of Order EA-13-1 09.

5.0

SUMMARY

As required by Order EA-13-1 09, the licensee provided an 01 P for designing and installing Phase 1 of a severe accident capable HCVS that provides venting capability from the wetwell during severe accident conditions, using a vent path from the containment wetwell to remove decay heat, vent the containment atmosphere (including steam, hydrogen, carbon monoxide, non-condensable gases, aerosols, and fission products), and control containment pressure within acceptable limits. The OIP describes a HCVS wetwell vent designed for those accident conditions (before and after core damage) for which containment venting is relied upon to reduce the probability of containment failure, including accident sequences that result in the loss of active containment heat removal capability or ELAP.

The NRC staff finds that the licensee's OIP for Phase 1 of Order EA-13-109 describes: plan elements and assumptions; boundary conditions; provisions for programmatic controls, training, drills and maintenance; and an implementation schedule that appear consistent with the guidance found in NEI 13-02 endorsed, in part, by JLD-ISG-2013-02 as an acceptable means for implementing phase 1 requirements of Order EA-13-1 09, subject to acceptable closure of the above open items.

6.0 REFERENCES

1. Order EA-13-1 09, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," June 6, 2013 ADAMS Accession No. ML13143A321 ).

2. Letter from NextEra to NRC, NextEra's Overall Integrated Plan for DAEC Nuclear Power Plant in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions Phase 1 (Order EA-13-109)," dated June 25, 2014 (ADAMS Accession No. ML14182A423).

3. SECY-11-0093, "Near-Term Report and Recommendations for Agency Actions Following the Events in Japan", (ADAMS Accession No. ML111861807).

4. SRM-SECY 0124, "Recommended Actions to be taken Without Delay From The Near-Term Task Force Report", (ADAMS Accession No. ML112911571).

5. SRM-SECY-11-0137, "Prioritization of Recommended Actions to be Taken in Response to Fukushima Lessons Learned", (ADAMS Accession No. ML113490055).

6. SRM-SECY-11-0093, "Staff Requirements- SECY-11-0093- Near-Term Report and Recommendations for Agency Actions following the Events in Japan," August 19, 2011 (ADAMS Accession No. ML112310021)

7. SECY-12-0025, "Proposed Orders and Requests for Information in Response to Lessons Learned from Japan's March 11, 2011, Great Tohoku Earthquake and Tsunami," February 17, 2012 (ADAMS Accession No. ML12039A103)

8. SRM-SECY 0025, "Staff Requirements - SECY 0025 - Proposed Orders and Requests for Information in Response to Lessons Learned from Japan's March 11, 2011, Great Tohoku Earthquake and Tsunami," March 9, 2012 (ADAMS Accession No. ML120690347)

9. Order EA-12-050, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents," March 9, 2012 (ADAMS Accession No. ML12054A694}

10. SECY-12-0157, "Consideration of Additional Requirements for Containment Venting Systems for Boiling Water Reactors with Mark I and Mark II Containments," November 26, 2012 (ADAMS Accession No. ML12325A704)

11. SRM-SECY-12-0157, "Staff Requirements- SECY-12-0157, "Consideration Of Additional Requirements For Containment Venting Systems For Boiling Water Reactors With Mark I And Mark II Containments", March 19, 2013 (ADAMS Accession No. ML13078A017).

12. NEI 13-02, "Industry Guidance for Compliance with Order EA-13-1 09," Revision 0, November 12, 2013 (ADAMS Accession No. ML13316A853)

13. JLD-ISG-2013-02, "Compliance with Order EA-13-1 09, 'Severe Accident Reliable Hardened Containment Vents,"' November 14, 2013 (ADAMS Accession No. ML13304B836)

14. Nuclear Regulatory Commission Audits Of Licensee Responses To Phase 1 of Order EA-13-1 09 to Modify Licenses With Regard To Reliable Hardened Containment Vents Capable Of Operation Under Severe Accident Conditions (ADAMS Accession No. ML14126A545)

15. Order EA-12-049, "Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," March 12, 2012 (ADAMS Accession No. ML12054A735).

16. Duane Arnold Energy Center Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-12-049 (Mitigation Strategies) (ADAMS Accession No. ML14007A676).

17. Letter from NextEra to NRC, NextEra Overall Integrated Plan for the Duane Arnold Energy Center in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049), dated February 28, 2013 (ADAMS Accession No. ML13063A148).

18. NUREG-1935, "State-of-the-Art Reactor Consequence Analyses (SOARCA)." Final Report (ADAMS Accession No. ML12332A058).

Principal Contributors: Bruce Heida Brian Lee Brett Titus Jerome Bettie Nageswara Karipineni Khoi Nguyen Steve Wyman Charles Norton Date: February 11, 2015

..* ML15006A319 *via email OFFICE NRR/JLD/JOMB/PM NRR/JLD/LA* OGC* NRR/DORL!LPL3-1/PM*

NAME CNorton Slent BHarris (NLO w/ comments) MChawla DATE 02/04/15 01/09/15 01/29/15 02/02/15 OFFICE NRR/JLD/JOMB/PM NRR/JLD/JCBB/BC* NRR/JLD/JERB/BC NRR/JLD/AD NAME JPaige SBailey BPham JMchale DATE 02/04/15 02/03/15 02/04/15 02/06/15 OFFICE NRR/JLD/AD NRR/JLD/JOMB/BC (A)

NAME JBowen MHalter DATE 02/06/15 02/11/15