ML20207K122

Advises That Upon Receipt of NRC Approval of Conceptual ATWS Design,Required ATWS Equipment Should Be Installed

ML20207K122
Person / Time
Site:	Arkansas Nuclear
Issue date:	09/21/1988
From:	Craig Harbuck Office of Nuclear Reactor Regulation
To:	Tison Campbell ARKANSAS POWER & LIGHT CO.
References
TAC-40567, TAC-62122, NUDOCS 8809280249
Download: ML20207K122 (4)

Text

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September 21, 1988 Docket No. 50-313 Mr. T. Gene Carpbell Vice President, Nuclear Operations Arkansas Power and Light Company Post Office Box 551 Little Feck, Arkansas 7??03

SUBJECT:

NRC RESPONSE TO THE B&W ATWS OWNERS GROUP (TACNOS.40567AND62122)

As you are aware, a reeting was held on August 17, 1988 between representatives of the B&W Owners Group (BWCG) and the NRC regarding the NRC staff's position on the various issues covered in the staff's generic B&W safety evaluation (SE) regarding the ATVS issue (10 CFR 50.62). The main point of disagreerent was the issue of power supply independence.

In this reeting, the staff presented three opticrs cn this riatter which it considered acceptable. These three approaches bave been formally docurented in the letter sent to the Chairm of the EWOG ATKS Comittee dated September 7,1988, a copy of which is attached.

In surrary, we stated in cur letter to Vr. Stalter our preference for adoption of the first option. Powever, you ray wish to consider each of the three options outlined in the enclosed letter in responding within the 90-day response period requested in our letter to you dated July 14, 1988 transriitting cur generic B&W ATYS SE. You should proeptly suteit your plant specific conceptual design for the optien you have selected. The NRC will review your conceptual design package within 30 days and provide you with an approval or disapproval with come nts. Since the generic design review has been corpleted and the options acceptable to the staff for resolving the ATKS power supply issue are sufficiently clear, it is our position that our safety evaluation of your plant-specific submittal does not have to precede your irplerentation of the required ATVS equiprent. Accordingly, your plant should install, upon receipt of our approval of your conceptual ATVS design, the required ATWS equipment during its next IQ, 8909280249 000921 DR ADOCK 05000313

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7 refueling outage.

If this cannot be accceplished, subnit your proposed imple-trentation schedule, including justification in accordance with 10 CFR 50.62(d),

for our review and approval.

If you have any questions en this ratter, please contact ce at 201-492-1337.

Sincerely,

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C. Craig Harbuck, Project Panager Project Directorate - IV Divisien of Reactor Projects - !!!,

!Y, Y and Special Projects

Enclosure:

As stated cc w/ enclosure:

See next page JD1 TRIBUT!0N ttocFerFTTi~

LFC PCR Local FOR FC4 Reading L. Rubenstein J. Calvo P. Ncenan C. Hart uck CGC-Rockville E. Jcrdan B. Grires ACRS (10)

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t refueling outage.

If this cannot be accorp11shed, subrit your proposed imple.

rentation schedule, including justification in accordance with 10 CFR 50.6?(d),

for our review and approval, i

If you have any questions on this Ntter, please Contact m at 301-492 1327, Sincerely, f.hef C. Craig Harbuck, Project Panager l

Project Directorate - IV f

Division cf Reactor Projects - !!!,

!Y, Y and Special Projects

Enclosure:

As stated cc w/ enclosure:

See next page e

Mr. T. Gene Campbell Arlansas Power t. Light Corpany Arkansas Nuclear One. Unit 1 l

CC:

Mr. Dan R. Howard Manager Licensing Arkansas Nuclear One P. O. Box 608 Russellville. Arkansas 72201 Pr. James M. Levine, Executive Director Nuclear Operations Arkansas Nuclear One P. O. Box 608 Russellville. Arkansas 72801 Mr. Nichclas S. Reynolds Bishop. Cook. Purcell l. Reynolds 1400 L Street. N.W.

Washington D.C.

20005-3502 Pr. Robert B. Borsum Babcock & Wilco Nuclear Power Generation Civision 1700 Reckville Pike. Suite 525 Rockville. Paryland 20E52 Resident Inspector U.S. Nuclear Regulatory Comission 1 Nuclear Plant Road Russellville. Arkansas 72801 Regional Administrator. Region IV U.S. Nuclear Regulatory Comissicn Office of Executise Director for Operations (11 Ryan Plaza Orive. Suite 1000 Arlington. Texas 76011 Mr. Frank Wilson Director Division of Environrental Health Protection Cepartrent of Health Arkansas Departrent of Health 4E15 West Parkham Street Little Rock. Arkansas 72201 Honorabla Williari Abernathy County Judge of Pope County Pope Ccunty Courthcuse Russellville. Arkansas 72801 j

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n Enclosure September 7,1988 Mr. L. C. Stalter Chairman EWOG/ATWS Corsnittee Davis Besse Nuclear Power Station 5501 Norths.R.2(MailStop3205)

Oak Harbor. Ohio 43449

SUBJECT:

AUGUST 17, 1988 84W/NRC ATWS MEETING The purpose of this letter is to sursr.arize major points addressed during the meeting which was held with the 84W ATWS owners group on August 17, 1988 to discuss the overall ATWS Rule requirements including power supply independence as related to the staff generic 84W ATWS SER.

Af ter a presentation by you and other members of the owners group, the staff provided clarification on various acceptable design options that would resolve the power supply independence issue.

We concluded that each licensee should consider each option as it epplies at each specific plant. The following options were presented by the staff:

1.

ProvideaDSS/AMSACdesignasdepictedintheviewgraph(Figure 1) presented at the meeting. This viewgraph shows the DSS /AMSAC being powered via a 480 volt bus with its own independent (i.e., not associated with the RTS) non-Class IE battery, rectifier and charger that provide 120 VAC to the ATWS circuitry.

2.

Provide a power source to the DSS as discussed above but non battery

backed, in addition, provide a discussion showing that for all loss of offsite power scenarios, the rods will be released through a loss of voltage to the 480 VAC holding mechanism.

Furthermore, show that the Emergency Feedwater Initiation and Control System (EFIC)(design (or its equivalent) meets the requirements of the ATWS Rule i.e.,

show that EFIC and AMSAC are equivalent in that they both perfers the same function).

If EFIC is powered through RTS 120 VAC buses then show by a failure modes and effects analysis that consnon mode failures will not propagate through the xneer supplies and disable both EFIC and the RTS. For this case, tie EFIC system has to be a Class 1E system.

3, Provide a Class 1E DSS that is powered by RTS xnver sources and show through a failure modes and effects analysis tiat cossnon mode failures will not propagate through the power supplies and disable both DS$ and the RTS. EFICistobetreatedasdiscussedin(2)above.

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.i L. C. Stalter,

8esed on our discussions to date, it is apparent that the power supply issue has delayed the implementation of the ATWS system at the B&W plants. We are concerned over this delay and strongly reconnend that the B&W licensees proceed with their planned ATWS implementation utilizing the option that will support the quickest resolution of the power supply independence issue. Option 1 will provide the most expeditious resolution and would clearly seet the power supply independence guidance published with the ATWS Rule. The approaches specified in options 2 and 3 are significantly more complex in that they involve the development of specific detailed failure modes and effects analyses. Such approaches could significantly delay resolution of the power supply independence issue (separation issue) and may ultimately lead to non-acceptance by the staff should unacceptable failure modes be identified.

Following receipt of each plant specific "conceptual" design package, the staff plans to review the package within 30 days and to approve, or disapprove with coments, the proposed design. This will be followed by the issuance of a safety evaluation upon receipt of a more detailed design package.

Since the generic design review has now been completed and the options for resolving the power supply issue are sufficiently clear, we have concluded that the staff safety evaluation does not have to precede the implemientation of the required ATWS equipment.

In other words, our safety evaluation would be a "post imple-surntation" review. All B&W plants, upon receipt of the NRC approval of the conceptual design, should install the ATWS equipment during their next refueling -

outage.

In special cases where this can't be accomplished, it should be brought to the attention of the staff for their review and approval per 10 CFR 50.62(d).

Sincerely, N

Gary Holahan, Acting Director Division of Reactor Projects - !!!, IV, V and Special Projects Office of Nuclear Reactor Regulation

Enclosures:

As stated

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