ML20217P328

Provides Initial Summary Response to Industry Comments on Interim Criteria Proposed by RES in 970303 Ril 174

ML20217P328
Person / Time
Issue date:	05/19/1997
From:	Holahan G NRC (Affiliation Not Assigned)
To:	Modeen D NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT &
References
NUDOCS 9708270308
Download: ML20217P328 (3)

Text

hMec W

p-

.4 UNITED STATES g,

Zi j

NUCLEAR REGULATORY COMMISSION o

WASHINGTON, D.C. 20555-0001

%*...../

~

May 19, 1997 Mr. David J. Hodeen a

Director Engineering Nuclear Generation Division Nuclear Energy Institute 1776 I Street, NW., Suite 400 Washington, D.C.

20006-3708

SUBJECT:

Industry Views on NRC Office of Nuclear Regulatory Research Proposed Interim Criteria for Reactivity Initiated Accidents

Dear Mr. Modeen:

This letter provides our initial summary response to the industry comments' on the interim criteria proposed by the NRC Office of Nuclear Regulatory Research (RES) in the March 3, 1997 Research Infor,,atior. Letter (RIL) No. 174, " Interim Assessment of Criteria for Analyzing Reactivity Accidents at High Burnup."

The Nuclear Energy Institute (NEI) letter of May 7,1997 primarily addresses a RES proposed interim criterion of a 100 cal /g peak fuel enthalpy increase to replace existing regulatory criteria for the threshold for initiation of fuel cladding damage during design basis reactivity event analyses.

The industry evaluation and position on the reactivity insertion accidents (RIAs), as provioed in the NEI letter of September 20, 1996, transmitting the Electric Power Research Institute (EPRI) Report TR-106387, " Evaluation of Irradiated Fuel During RIA Simulation Tests," and in the NEI letter of April 8,1996, have been considered in this response.

First, RIL 174 acknowledges that available past and current research experiments are not directly applicable to U.S. commercial light water reactor fuel and the predicted accident conditions for U.S. LWRs. The RIL also acknowledges -that NRR performed an initial safety significance evaluation which concluded that there is no significant impact on public health and

-safety.because of the low probability of the event and the high likelihood that core coolability would be maintained.

We believe that the RIL is also consistent with the industry evaluation and stated position that RIAs.are highly unlikely and that the radiological consequences from postulated high burnup fuel failures are limited.

You expressed concern that currently licensed and future interim reload core designs will unduly require the development and use of formally approved

~ three-dimensional (3-D) neutronic kinetics calculational models and

\\

methodologies. As you state, both industry and NRC-sponsored neutronics t

calculations have been performed which have shown that fuel enthalpy during RIAs for contemporary core designs will be lower than 100 cal /g.

You state that these calculations have been performed using computer codes and methodologies which-have not been reviewed and approved by the NRC.

g, hN ~

9708270308 970519 i

PDR REVGP ERONUMRC f

PDR gm gg-3 L

1

(.

\\

Mr. David J. Modeen We thank you for your comments and will consider them in conjunt, tion with the Ril No. 174 recommendations while developing a regulatory position, if the NRC ultimately decides to place new requirements for RIAs an licensees, any costs, such as additional 3-D analyses, will be addressed as part of the backfit decision.

However, for your information, a number of 3-D transient codes are available and several have been accepted, aith restrictions on allowable feedback mechanisms (e.g. no void feedback without experimental justification), for licensing applications. Also, we are currently reviewing a state of the art 3D-kinetics code.

Some of these codes have been benchmarked against standard reference solutions, such as the NEACRP 3-D LWR Transient Benchmark. A summary list of codes which have been or are under review for referencing by the NRC is provided in the enclosure.

i As you know, we are working on a more complete response to earlier submittals by NEl and the industry and expect to provide a further response soon. We agree that the industry and the NRC should continue to interact on this generic issue, and we welcome your comments.

As you suggest, we are willing to meet with you and your task force.

Please contact Laurence Phillips at (301) 415-3232 if you have any questions about this response.

Sincerely, Original Signed By:

Gary M. Holahan, Director Division of Systems Safety and Analysis Office of Nuclear Reactor Regulation

Enclosure:

As stated DISTRIBUTION:

SRXB R/F File; Center:

PDR EKendrick SWu

+rn.. i n -

JLyons GHolahan ACThadani EKendrick R/F DOCUMENT NAME:

G:RIL &NEl.LTR

• See previous concurrence

/)

4 SRX fdSSA 0FFICE:

SRXB:DSSA SRXB:DSSA SRXB:DSSA JLyp'Q)DSSA fs\\

G olahan NAME:

EKendrick* SWu*

LPhillips*

DATE:

5/15/97 5/16/97 5/15/97 5/n/97

/g/97 1

- t

• L, ji 0FFICIAL RECORD COPY ENCLOSURE Partial List of Vendor / Licensee / Industry 3D Transient Codg1

yendor/ Licensee / Industry Groug Code Name Status Comments ABB/CE-BWR RAMONA-38-SCP2 Revieweo RPA-89-112, SER (4/96)

PWR.

HERMITE Reviewed CENPD-188 Framatome-(B&W)

NEMO-K Submitted BAW-10221P, Under review GE TRAC-G.

In review Audited for stability Siemens BWR RAMONA-3 non-U.S.

Use examined during-inspection PWR g

-West' Tuse TWINKL WCAP-8020 EPRI-ARR0TTA Reviewed Accepted for Rod Eject evaluation at McGuire/ Catawba National' Labs BNL-RAMONA-4B confirmatory MEKIN confirmatory:

International-

-Paul-Scherr-Institute ARR0TTA non-U.S.

NEA

. PANDA non-U.S.

Benchmark refererce

_ - _