80 FR 12649 - Compliance With Phase 2 of Order EA-13-109

NUCLEAR REGULATORY COMMISSION

Federal Register Volume 80, Issue 46 (March 10, 2015)

The U.S. Nuclear Regulatory Commission (NRC) is issuing for public comment its Japan Lessons-Learned Division (JLD) draft interim staff guidance (ISG), ``Compliance with Phase 2 of Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions,'' (JLD- ISG-2015-01). This draft JLD-ISG would provide guidance and clarification to assist nuclear power reactor licensees identify measures needed to comply with Phase 2 requirements of the ``Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions,'' (Order EA-13- 109) to have either a vent path from the containment drywell or a strategy that makes it unlikely that venting would be needed from the drywell before alternate reliable containment heat removal and pressure control is reestablished.

[Federal Register Volume 80, Number 46 (Tuesday, March 10, 2015)]
[Notices]
[Pages 12649-12651]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2015-05436]


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NUCLEAR REGULATORY COMMISSION

[NRC-2015-0048]


Compliance With Phase 2 of Order EA-13-109

AGENCY: Nuclear Regulatory Commission.

ACTION: Draft interim staff guidance; request for comment.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing for 
public comment its Japan Lessons-Learned Division (JLD) draft interim 
staff guidance (ISG), ``Compliance with Phase 2 of Order EA-13-109, 
Order Modifying Licenses with Regard to Reliable Hardened Containment 
Vents Capable of Operation under Severe Accident Conditions,'' (JLD-
ISG-2015-01). This draft JLD-ISG would provide guidance and 
clarification to assist nuclear power reactor licensees identify 
measures needed to comply with Phase 2 requirements of the ``Order 
Modifying Licenses with Regard to Reliable Hardened Containment Vents 
Capable of Operation Under Severe Accident Conditions,'' (Order EA-13-
109) to have either a vent path from the containment drywell or a 
strategy that makes it unlikely that venting would be needed from the 
drywell before alternate reliable containment heat removal and pressure 
control is reestablished.

DATES: Submit comments by April 9, 2015. Comments received after this 
date will be considered, if it is practical to do so, but the 
Commission is able to ensure consideration only for comments received 
before this date.

ADDRESSES: You may submit comment by any of the following methods 
(unless this document describes a different method for submitting 
comments on a specific subject):
     Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2015-0048. Address 
questions about NRC dockets to Carol Gallagher; telephone: 301-415-
3463; email: [email protected]. For technical questions, contact 
the individual listed in the FOR FURTHER INFORMATION CONTACT section of 
this document.
     Mail comments to: Cindy Bladey, Office of Administration, 
Mail Stop: OWFN-12-H08, U.S. Nuclear Regulatory Commission, Washington, 
DC 20555-0001.
    For additional direction on obtaining information and submitting 
comments, see ``Obtaining Information and Submitting Comments'' in the 
SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: Rajender Auluck, Office of Nuclear 
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001; telephone: 301-415-1025; email: [email protected].

SUPPLEMENTARY INFORMATION:

I. Obtaining Information and Submitting Comments

A. Obtaining Information

    Please refer to Docket ID NRC-2015-0048 when contacting the NRC 
about the availability of information regarding this document. You may 
obtain publicly-available information related to this action by the 
following methods:
     Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2015-0048.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may access publicly-available documents online in the NRC 
Library at http://www.nrc.gov/reading-rm/adams.html. To begin the 
search, select ``ADAMS Public Documents'' and then select ``Begin Web-
based ADAMS Search.'' For problems with ADAMS, please contact the NRC's 
Public Document Room (PDR) reference staff at 1-800-397-4209, 301-415-
4737, or by email to [email protected]. The ADAMS accession number 
for each document referenced in this notice (if that document is 
available in ADAMS) is provided the first time that a document is 
referenced. The draft JLD-ISG-2015-01 is available in ADAMS under 
Accession No. ML15051A143. The ISG for complying with Phase 1 
requirements of the order (JLD-ISG-2013-02) was issued on November 14, 
2013 (ADAMS Accession No. ML13304B836).
     NRC's PDR: You may examine and purchase copies of public 
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 
Rockville Pike, Rockville, Maryland 20852.
     NRC's Interim Staff Guidance Web site: JLD-ISG documents 
are also available online under the ``Japan Lessons Learned'' heading 
at http://www.nrc.gov/reading-rm/doc-collections/isg/japan-lessons-learned.html.

B. Submitting Comments

    Please include Docket ID NRC-2015-0048 in the subject line of your 
comment submission, in order to ensure that the NRC is able to make 
your comment submission available to the public in this docket.
    The NRC cautions you not to include identifying or contact 
information that you do not want to be publicly disclosed in your 
comment submission. The NRC posts all comment submissions at http://www.regulations.gov as well as entering the comment submissions into 
ADAMS. The NRC does not routinely edit comment submissions to remove 
identifying or contact information.
    If you are requesting or aggregating comments from other persons 
for submission to the NRC, then you should inform those persons not to 
include identifying or contact information that they do not want to be 
publicly disclosed in their comment submission. Your request should 
state that the NRC does not routinely edit comment submissions to 
remove such information before making the comment submissions available 
to the public or entering the comment submissions into ADAMS.

II. Background

    The NRC developed draft JLD-ISG-2015-01 to provide guidance and 
clarification to assist nuclear power reactor licensees with the 
identification of methods needed to comply with Phase 2 requirements in 
Order EA-13-109, ``Order Modifying Licenses with Regard to Reliable 
Hardened Containment Vents Capable of Operation under Severe Accident 
Conditions'' (ADAMS Accession No. ML13130A067). The draft ISG would not 
be a substitute for the requirements in Order EA-13-109, and compliance 
with the ISG would not be a requirement. This ISG is being issued in 
draft form for public comment to involve the public in development of 
the implementing guidance.
    The accident at the Fukushima Dai-ichi nuclear power station 
reinforced the importance of reliable operation of containment vents 
for boiling-water reactor (BWR) plants with Mark I and Mark II 
containments. As part of its response to the lessons learned from the 
accident, on March 12, 2012, the NRC issued Order EA-12-050 (ADAMS 
Accession No. ML12056A043) requiring licensees to upgrade or install a 
reliable hardened containment venting system (HCVS) for Mark I and Mark 
II containments. The requirements in Order EA-12-050 for licensees with

[[Page 12650]]

BWR plants with Mark I and Mark II containments were intended to 
increase the reliability of containment venting to support decay heat 
removal from the reactor core and provide protection against over-
pressurization of the primary 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 licensees used the venting systems 
during severe accident conditions.
    The NRC staff presented the Commission with options to address 
these issues in SECY-12-0157, ``Consideration of Additional 
Requirements for Containment Venting Systems for Boiling Water Reactors 
with Mark I and Mark II Containments'' (issued November 26, 2012, ADAMS 
Accession No. ML12325A704). The options presented in SECY-12-0157 
included continuing with the implementation of Order EA-12-050 for 
reliable hardened vents (Option 1); requiring licensees to upgrade or 
replace the reliable hardened vents required by EA-12-050 with a 
containment venting system designed and installed to remain functional 
during severe accident conditions (Option 2); requiring licensees with 
BWR Mark I and Mark II containments to install an engineered filtered 
containment venting system intended to prevent the release of 
significant amounts of radioactive material following the dominant 
severe accident sequences (Option 3); and pursuing development of 
requirements and technical acceptance criteria for performance-based 
confinement strategies (Option 4). The NRC staff provided an evaluation 
considering various quantitative analyses and qualitative factors 
related to the options and recommended the Commission approve Option 3 
to require the installation of an engineered filtering system. One 
issue not specifically addressed within SECY-12-0157 was the importance 
of water addition to cool core debris as part of severe accident 
management for BWR's with Mark I and II containments. The NRC staff 
acknowledged in SECY-12-0157 that in the longer-term rulemaking 
associated with any of the options presented, the NRC could consider 
adding requirements for the capability of core debris cooling during 
severe accident scenarios.
    In the staff requirements memorandum (SRM) for SECY-12-0157, dated 
March 19, 2013 (ADAMS Accession No. ML13078A017), the Commission 
directed the staff to: (1) Issue a modification to Order EA-12-050 
requiring BWR 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, and (2) develop a 
technical basis and rulemaking for filtering strategies with drywell 
filtration and severe accident management of BWR Mark I and II 
containments. The NRC subsequently issued Order EA-13-109 to define 
requirements and schedules for licensees for BWRs with Mark I and Mark 
II containments to install severe accident capable containment venting 
systems. The NRC staff also initiated development and evaluation of 
other possible regulatory actions identified in the Commission's SRM 
for SECY-12-0157, including the development of a technical basis in 
support of a Containment Protection and Release Reduction (CPRR) 
rulemaking.
    Order EA-13-109, in addition to requiring a reliable HCVS to assist 
in preventing core damage when heat removal capability is lost (the 
purpose of EA-12-050), will ensure that venting functions are also 
available 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. The safety improvements to Mark I and Mark II containment 
venting systems required by Order EA-13-109 increase confidence in 
licensees' ability to maintain the containment function following core 
damage events. Although venting the containment during severe accident 
conditions could result in the release of radioactive materials, 
venting could also prevent containment structural failures and gross 
penetration leakage due to overpressurization that would hamper 
accident management (e.g., continuing efforts to cool core debris) and 
ultimately result in larger, uncontrolled releases of radioactive 
material.
    In recognition of the relative importance of venting capabilities 
from the wetwell and drywell, a phased approach to implementation is 
being used to minimize delays in implementing the requirements 
originally imposed by Order EA-12-050. Phase 1 involves upgrading the 
venting capabilities from the containment wetwell to provide reliable, 
severe accident capable hardened vents to assist in preventing core 
damage and, if necessary, to provide venting capability during severe 
accident conditions. Phase 2 involves providing additional protection 
during severe accident conditions through installation of a reliable, 
severe accident capable drywell vent system or the development of a 
reliable containment venting strategy that makes it unlikely that a 
licensee would need to vent from the containment drywell during severe 
accident conditions. For implementation of Phase 1 order requirements, 
the NRC issued JLD-ISG-2013-02 on November 14, 2013 (78 FR 70356), 
which endorsed, with clarifications, the methodologies described in the 
industry guidance document Nuclear Energy Institute (NEI) 13-02, Rev. 0 
(ADAMS Accession No. ML13316A853). As required by the order, licensees 
submitted their site-specific overall integrated plans by June 30, 
2014. The NRC is currently reviewing these plans and expects to 
complete those reviews by June 2015.
    The focus of this ISG is to provide guidance for Phase 2 
requirements of the order. Some proposed approaches to implement Phase 
2 requirements of the order include the addition of water to the 
drywell during severe accident conditions. Evaluations performed by the 
NRC and industry in conjunction with the CPRR rulemaking show that 
water addition during severe accident conditions provides benefits that 
include reducing temperatures and cooling molten core debris. In SECY-
12-0157, the NRC discussed various risk assessments by the NRC and 
industry that have concluded that adding water to the drywell reduces 
the likelihood of release of radioactive materials for those severe 
accident scenarios that involve fuel melting through the reactor 
vessel. The water added to the drywell cools the molten fuel and can 
arrest the melting fuel's progression and reduce the likelihood of a 
loss of the containment function through liner melt-through, 
containment over-pressurization failure, and containment over-
temperature failure. In addition to the benefits associated with 
containment protection, recent technical evaluations performed by both 
the industry and the NRC indicate that including the capability of 
timely severe accident water addition (SAWA) results in a substantially 
lower drywell temperature for consideration in designing the drywell 
vent. Therefore, SAWA will facilitate implementation of Phase 2 of 
Order EA-13-109 by establishing the design conditions for a drywell 
vent and supporting severe accident water management (SAWM) for

[[Page 12651]]

licensees choosing to pursue that option as a strategy that makes it 
unlikely that a licensee would need to vent from the drywell.
    On December 10, 2014, NEI submitted NEI 13-02, ``Industry Guidance 
for Compliance with Order EA-13-109,'' Rev. 0E2 (ADAMS Accession No. 
ML1434A374) to assist nuclear power licensees with the identification 
of measures needed to comply with the requirements of Order EA-13-109 
regarding reliable hardened containment vents capable of operation 
under severe accident conditions. The NEI document includes guidance 
for implementing order requirements for both Phase 1 and Phase 2, 
including the industry's proposed approach to use the SAWA and SAWM 
strategies to control the water levels in the suppression pool and 
maintain capabilities to address over-pressure conditions without a 
severe accident drywell vent. As described in the draft ISG, some 
issues remain the subject of ongoing discussions as part of finalizing 
the guidance. These include: (1) Availability of power and functional 
requirements for the SAWA-related installed and portable equipment, (2) 
duration of time for preservation of the wetwell vent for the SAWM 
strategy, and (3) alternate control of containment conditions during 
recovery from the severe accident. The NRC intends to continue 
discussions with stakeholders prior to finalizing the ISG for Phase 2 
of the order and endorsing, with clarifications and exceptions if 
necessary, the methodologies described in the industry guidance 
document NEI 13-02, Rev. 0E2.

    Dated at Rockville, Maryland, this 2nd day of March 2015.

    For the Nuclear Regulatory Commission.
Jack R. Davis,
 Director, Japan Lessons-Learned Division, Office of Nuclear Reactor 
Regulation.
[FR Doc. 2015-05436 Filed 3-9-15; 8:45 am]
 BILLING CODE 7590-01-P