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c' Mr. J. C. McKinley c
Advisory Committee on Reactor Safeguards hg U.S. Atomic Energy Constission u'Eg S
Washington, D.C. 20545
Dear Mr. McKinley:
From the information received during the May 3 & 4 Grand Gulf Subcommittee meeting I conclude now that there is sufficient justification to proceed with the construction of said Nuclear Station.
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With reference to the Mark-III containment recently obtained GE results viewed in the context of the current state of knowledge suggest reasonable assurance that there are no problems to be expected. I would recommend, nevertheless, that the finally arrived-at Mark-III confirmations test program be closely followed by the GE subcommittee of the ACRS.
With reference to ECCS GE suggested that the currently underway BDHT program will address my question of system's effects and adequacy of the GE evaluation model in that respect. Since, if this turns out to be a problem there is a number of ways by which it can be fixed, I do not recommend delaying this application any further. I do recommend, however, very strongly, that the GE subcommittee closely follow this program as well as the standard problems in which GE is participating.
If you have any questions please call me at 317+749-2602.
Sincerely, K.
T.G. Theofanous TGT:ke ec:
C.W. Solbrig
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Filed: 1) Grand Gulf
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0FFICIAL USE ONLY JCM:bjw:May 6, 1974 Fr4 ject:
Grand Gulf Socisar Station, Units 1 and 2 Status:
Construction Permit Review - Letter requested at this meeting - Third meeting with ACRS
Background:
November 27, 1972 - Application and PSAR received by ACRS October 25, 1973 - ACRS" Subcommittee meeting December 21 & 22, 1973 - ACRS Site visit and Subcommittee meeting January 12, 1974 - Regulatory Staff report received January 17.6118, 1974 - ACRS Subcommittee meeting February 7,1974 - ACRS meeting March 6, 1974 - ACRS Subcommittee meeting March 7,1974 - ACR$ meeting April 12, 1974 - Supplement No. I to the Regulatory Staff Report received May 3 & 4, 1974 - ACKS Subcommittee meeting May 9, 1974 - ACKS meeting The Mississippi Power and 1.ight Company has applied for a permit to construct the Grand Gulf Nuclear Station, Units 1 and 2 at a site about 25 miles south of VicMaburg, Mississippi. The units will be BWR/6 models, rated at 3833 MWt and housed in Mark III containments.
This is the first application of BWR/6, Mark III reviewed by the Committee.
The 2300 acre site is in a sparsely populated rurcl area in Claiborne County Mississippi on the east bank of the Mississippi River. The SPI for this site is 0.02 making it comparable to Diablo Canyon, Edwin 1.
Hatch, and the FFTF. The minimum exclusion distance is 752 meters and the low population zone extends to two.siles. The total population within the low population zone is 190 people. The nearest population center is Vicksburg about 25 miles away.
The Staf f, its consultants (USCS), and the applicant have examined the seismic potantial of the Grand Gulf site. Baced on several kinds of iy evidence it has been concluded that the type of earthquakes that occurred at New Madrid, Missouri in 1811 and 1812 probably would not occur in the region south of Memphis, Tennessee. The applicant has studied the seismic history in the region of the site and has proposed a SSE ground accelerations of 0.15g for structures founded on the Catahoula formation and 0.20g for structures founded in geologic layers above the Catahoula formation. The i
l Staff and its consultants believe these values are suitably conservative.
The Subcommittee's consultants reviewed the material provided by the Staff and applicant and agree that the likelihood of a New Madrid earthquake at the site in quite remote and that the ground acceleration values proposed are appropriate; they emphasized, however, that great care must
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be taken in the selection of the frecuency response sometrum and earticular attontion should be given to the low frequency (~ 2 socorid period) gecond omygg,tg sunnAut >
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Form AEC-518 (Rev 9 53) AECM 0240
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' Since the full Comittee has not heard any detafis of this site, the applicant has been requested to make a presentation on this metter.
The Subcommittee's consultants have had many questions on the performance of the Mark III pressure suppression containment system.
At the last Subcommittee meeting it appeared that all of the outstanding questions were resolved, su) ject to satisfactory completion of the confirmatory test program, and the consultants agreed that construction should be permitted to proceed. Copies of the analyses provided by GE are attached for your information.
The applicant has revised his proposed design of the guard pipes that will be provided for the ten high pressure process lines that pass from the drywell thes ugh containment. The new design includes hand holes in the guard pipe outside of containment, in the teactor Building. Tbts represents a potential leak path directly from the drywell to the Reactor Building. Location of the hand holes inside of containmer.t sould result in overpressurizing the containment if there aus major leakage. The applicant has been requested to make a presentation on this topic to the Consni t te e.
The applicant proposes to use some conventional calcium-magnesium thermal insulating materie.1 on some piping in the containment. The question was raised regarding the potential for this material to find its way into the suppression pool and block strainers, pumps, or valves in the various ECCS systems taking water from this source. The applicant claims that the material will float en the water surface and not be drawn into the systems.
He has been asked to make a presentation on foreign materials that might find their way into the suppression pool and their effect on ECCS operation.
The applicant has locked at the proposed revision of Regulatory Guide 1.7 and has drafted a potential modification of the drywell air circulation system that could be proposed if Regulatory Guide 1.7 is modified. This revision is not beine proposed at this time. The applicant will make a presentation describing it, however.
The applicant has made a concise comparison of the effects on ECCS performance of increasing the water flow rates in the various systems by 10, 25, and 50%. of nuclear power uncertainties, and of 7x7 and 8x8 fuel assemblies. He will make a presentation of this material (see attachments to this status report).
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Form AEC-518 lRev. 9-53) AECM 0240
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Of7ICIAL USE ONLY The normal electrical power for this plant is provided by three 500 kV and one 115 kV lines coming from four separate sources on separate rights-of-way. Each unit is provided with three diesel generaters, only two of which are required to operate in the DBA.
f With the exception of the hydrogen Otegulatory Guide 1.7) goestion, it 1
appears that all other major issues have been resolved and the Committee can consider preparing a report favorable to the constructies of the Grand Gulf Nuclear Station, Units 1 and 2.
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Form AEC-518 (Rev. 9-531 AECM 0240 e.o oes-na-sionH
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