ML20008F494

Forwards Mechanical Engineering Branch & Hydrologic & Geotechnical Engineering Branch Requests for Addl Info for Review of FSAR

ML20008F494
Person / Time
Site:	Grand Gulf
Issue date:	04/09/1981
From:	Tedesco R Office of Nuclear Reactor Regulation
To:	Mcgaughy J MISSISSIPPI POWER & LIGHT CO.
References
NUDOCS 8104210086
Download: ML20008F494 (5)

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Docket Nos.: 50-416/417 c

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Mr. J. P. McGaughy, Jr.

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h IS8 vh %Qg/g 8 Assistant Vice President - Nuclear Production Mississippi Power and Light Company P. O. Box 1640 g-Jackson, Mississippi 39205 9

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SUBJECT:

REQUEST FOR ADDITION AL INFORMATION - GRAND GLLF NUCLEAR STATION, UNITS 1 AND 2 As a result of our review of the information contained in the Final Safety Analysis Report for the Grand Gulf Nuclear Station, Units 1 and 2, we have developed the enclosed request for additional information. Included are questions from the Mechanical Engineering Branch and the Hydrologic and Geotechnical Engineering Branch.

We request that you amend your Final Safety Analysis Report to reflect your responses to the enclosed requests as soon as possible and to inform the Project Manager, Joseph A. Martore, of the date by which you intend to respond.

Sincerely.

Ortshed dgned W hsert I. Tedeseo Robert L. Tedesco, Assistant Director for Licensing Division of Licensing

Enclosure:

As stated cc: See next page 8104210 og

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APR 9 1981 Docket Nos.: 50-416/417 Mr. J. P. McGaughy, Jr.

Assistant Vice President - Nuclear Production Mississippi Power and Light Company P. O. Box 1640 Jackson, Mississippi 39205

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION - GRAND GULF NUCLEAR STATION, UNITS 1 AND 2 As a result of our review of the information contained in the Final Safety Analysis Report for the Grand Gulf Nuclear Station, Units I and 2, we have developed the enclosed request for additional information.

Included are questions from the Mechanical Engineering Branch and the Hydrologic and Geotechnical Engineering Branch.

We request that you amend your Final Safety Analysis Report to reflect your responses to the enclosed requests as soon as possible and to inform the Project Manager, Joseph A. Partore, of the date by which you

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'ntend to respond.

Sincerely, Robert L. Tedesco, Assistant Director for Licensing Division of Licensing

Enclosure:

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APR 9 1981 Request for Addition'al Information - Geotechnical Engineering Grand Gulf Nos.1 & 2 Nuclear Station Docket Numbers 50-416/417 362.6 Your response to item 362.1 (page Q&R 2.5-7, Amendment 25)

(2. 5. 4. 2.1 )

states that, on assigning an undrained shear strength of 4000 psf for the Catahoula formation, use of Skempton's c/p ratio would result in an OCR for the Catahoula of an average of 2.

The staff concurs with this statement. However, the p-q plot illustrated on figure 2.5 65 for the unconsolidated-undrained triaxial shear tests for the Catahoula material is not clear.

Is Figure 2.5-65 an effective stress plot? What do the data points on the q axis (p=0) of this figure signi fy? Provide a plot of the effective stress paths for the consolidated undrained p-q strength tests to verify that the OCR for the Catahoula is in excess of 2.

l 362.7 Ycur response to item 362.5 (page Q&R 2.5-14, Amendment 30) is (2.5.4.13.1 )

not complete.

Indicate what measured value of differential settledent would cause code allowable stresses to be exceeded for individual buildings and buried piping and require notification of NRC. Provide a table of these values and the limiting stress criteria. Update the l

plots which show settlement recorded to date versus time; this is particularly important since construction of Unit 2 was still unde'rway.

when your response to Question 362.5 was being developed.

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MECHANICAL ENGINEERING BRANCH

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Requ:st for Additional Information 110.48 There are several safety systems connected to the reactor coolant pressure boundary that have design pressure below the rated reactor coolant system (RCS) pressure. There are also some systems which are rated at full reactor pressure on the discharge side of pumps but have pump suction below RCS pressure. In order to protect these systems from RCS pressure, two or more isolation valves are placed in series to form the interface between the high pressure RCS and the icw pressure systems. The leak tight integrity of these valves must be ensured by periodic leak testing to prevent exceeding the design pressure of the low pressure systems thus causing an inter-system LOCA.

l Pressure isolation valves are required to be category A or AC per IWY-2000 and

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to meet the appropriate requirtments of IWV-3420 of Section XI of the ASME Code except as discussed below.

Limiting Conditions for Operation (LCO) are required to be added to the technical specifications which will require corrective action i.e., shutdown or system isolation when the final approved leakage limits are not met. Also surveillance requirements, which will state the acceptable leak rate testing frequency, shall be provided in the technical specifications.

Periodic leak testing of each pressure isolation valve is required to be performed at least once per each refueling outage, after valve maintenance prior to return to service, and for systems rated at less than 50% of RC5 design pressure each time the valve has moved from its fully closed position unless justification is given. The testing interval should average to be approximately c e year. Leak testing should also be performed after all disturbances to the valves are complete, prior to reaching power operation following a refusling outage, maintenance and etc.

The staff's present position on leak rate limiting conditions for operation must be equal to or less than 1 gallon per minute for each valve (GPM) to ensure the integrity of the valve, demonstrate the adequacy of the redundant pressure isolation function and give an indication of valve degradation over a finite period of time. Significant increases over this limiting valve would be an indication of valve degradation from one test to another.

Leak rates higher than 1 GPM will be considered if the leak rate changes are below 1 GPM above the previous test lesk rate or system design precludes measuring 1 GPM with sufficient accuracy. These items will be reviewed on a case by case ba sis.

The Class 1 to Class 2 boundary will be considered the isolation point which must be protected by redundant isolation valves.

In cases where pressure isolation is provided by two valves, both will be inde-pendently leak tested. When three or more valves provide isolation, only two of the valves need to be leak tested.

Provide a list of all pressure isolation valves included in your testing program along with four sets of Piping and Instrument Diagrams which describe your reactor coolant system pressure isolation valves. Also discuss in detail how your leak testing program will conform to the above staff position.

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l 110.4g It is the staff's position that all essential safety-related instrumentation lines should be included in the vibration monitoring program during pre-operational or start-up testing. We require that either a visual or instrumented inspection (as appropriate) be con-ducted to identify any excessive vibration that will result in fatigue failure.

Provide a list of all safety-related small bore piping and instrumentation lines that will be included in the initial test vibration monitoring program.

The essential instrumentation lines to be inspected should include (but are not limited to) the following:

a) Reactor pressure vessel level indicator instrumentation lines (used for monitoring both steam and water levels).

b) Main steam instrumentation lines for monitoring main.

steam flow (used to actuate main steam isolation valves during high steam flow).

c) Reactor core isolation cooling (RCIC) instrumentation lines en the RCIC steam line outside containment (used to monitor high steam flow and actuate isolation).

d) Control rod drive lines inside containment (not normally pressurized but required for scram).

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APR 9' 1981 Mr. J. P. McGaughy Assistant Vice President - Nuclear Production Mississippi Power & Light Company P. O. Box 1640 Jackscn, Mississippi 39205 cc: Robert B. McGehee, Esq.

Wise, Carter, Child, Steen & Caraway P. O. Box 651 Jackson, Mississippi 39205 Troy B. Conner, Jr., Esq.

Conner, Moore & Corber 1747 Pennsylvania Avenue, N. W.

Washington, D. C.

20006 Mr. Adrian Zaccaria, Project Engineer Grand Gulf Nuclear Station Bechtel Power Corporation Gaithersburg, Maryland 20760 Mr. Alan G. Wagner, Resident Inspector Route 2 Box 150 Port Gibson, Mississippi 39150 Mr. N. L. Stampley, Sr. Vice President Engineering, Production & Construction P.O. Box 1640 Jackson, Mississippi 39205 Mr. L. F. Dale Nuclear Project Manager P.O. Box 1640 Jackson, Mississippi 39205 Mr. John Richardson P. O. Box 1640 Jackson, Mississippi 39205 l

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