ML20198S945

Forwards RAI Re Grinnell Hydraulic Snubbers at Mcguire Nuclear Station,Units 1 & 2

ML20198S945
Person / Time
Site:	Mcguire, McGuire
Issue date:	10/30/1997
From:	Nerses V NRC (Affiliation Not Assigned)
To:	Barron H DUKE POWER CO.
References
TAC-M97753, TAC-M97754, NUDOCS 9711140175
Download: ML20198S945 (6)

Text

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( October 30, 1997 Mr. H. B. Barron Vice President - McGuire Site i Duke Energy Corporation 12700 Hagers Ferry Road Huntersville, North Carolina 28078

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING MCGUIRE NUCLEAR STATION, UNITS 1 AND 2, GRINNELL HYDRAULIC (

SNUBBERS (TAC NOS. M97753 AND M97754)

Dear Mr. Barroi :

The NRC staf' has reviewed your response of August 28,1997, to the staffs previous request for additional inform 0 tion (RAl) of June 16,1997, pertaining to the Grinnell hydraulic snubbers at McGuire Nuclear Station, Units 1 and 2. The staff dete mined that the enclosed RAI is necded in order to complete its review of this lasue.

Sincerely, ORIGINAL SIGNED BY:

Victor Narses, Senior Project Manager Project Directorate ll-2 Divisicn of Reactor Projects - t/II C F ;e of Nuclear Reactor Regulation Docket Noe 50-369 and 50-?70

Enclosure:

As stated DISTRIBUTION YCLi LDeeket9lWA OGC cc wiencl: See next page PUBLIC ACRS P0ll-2 Reading JJohnson,Ril BBoger COgle,Ril HBerkow VNerses DOCUMENT NAME: G:\MCGUIRE', SNUBBER.RAI To receive a copy of this document, indicate in the box C= Copy w/o tidachment/onclosure E= Copy with attachment! enclosure N = No copy ' _

oFHCE Pp3 2(IPM E PDil-2/LA n h E PDt_t@f5 E NAME E h LBERRY H NR h DATE /p /A f)/97 h/ hD/97 [jf 3 : /97 OFFICIAL RECORD COPY IT i

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l soo no;p p \ UNITED STATES s* NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30eeHooi

% ,,, g October 30, 1997 Mr. H. B. Barron Vice rresideat - McGuire Site Duke Energy Copration 12700 Hagers Ferry Road Huntersville, North Carolina 28078

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING MCGUIRE NUCLEAR STATION, UNITS 1 AND 2, GRINNELL HYDRAULIC SNUBBERS (TAC NOS. M97753 AND M97754)

Dear Mr. Barron:

The NRC staff has reviewed your response of August 28,1997, to the staff's previous request for additional inforrnation (RAI) of June 16,1997, pertaining to the Grinnell hydraulic snubbers at McGuire Nuclear Station, Unie l and 2. The staff determined that the enclosed RAI is needed in order to complete itn rev:s ; c' this issue.

S b a rely, h<j Victor Nerses, Senior Project Manager Project Directorate ll-2 Division of Reactor Projects - 1/li Offico of Nuclear Reactor Regulation Docket Nos: 50-369 and 50-370

Enclosure:

As stated cc w/ encl: See next page IL

McGuire Nuclear Station i

cc:

Mr. Paul R. Newton = Ms. Karen E. Long

- Legal Departme' ' (PB05E) Assistant Attorney General Duke Energy Cnporation North Carolina Department of 422 South Church Street Justice Charlotte, North Carolina 28242 P. O. Box 629 Raleigh, North Carolina 27602 County Manager of Mecklenburg County Mr. G. A. Copp 720 East Fourth Street Licensing - EC050 Charlotte, North Carolina 28202 Duke Energy Corporation  !-

526 South Church Street Michael T. Cash Charlotte, North Carolina 28242 Regulatory Compliance Manager Duke Energy Corporation Regional Administrator, Region ll McGuire Nucicar Site _

ll.S. Nuclear Regulatory Commission 12700 Hagsrs Ferry Road Atlanta Federal Center Huntersville, North C.rolina 28078 61 Forayth Street, S.W., Suite 23T85 Atlanta, Georgia 30303 J. Michael McGarry, Ill, Esquire Winston and Strawn Elaine Wathen, Lead REP Planner 1400 L Street, NW. Division of Emergency Management Washington, DC 20005 116 West Jones Street Raleigh, North Carolina 27603-1335 Senior Resident inspector clo U.S. Muclear Regulatory Mr. Richard M. Fry, Director Commi%0n Division of Radiation Protection 12700 Hagers Ferry Road North Carolina Department of Huntersville, North Carolina 28078 Environment Health and Natural Resources Mr. Peter R. Harden, IV 3825 Barrett Drive Account Sales Manager Raleigh, North Carolina 27609-7721 Westinghouse Electric Corporation Power Systems Field Sales Mr. T. Richard Puryear P, O. Box 7288 Owners Group (NCEMC)

Charlotte, North Carolina 28241 Duke Energy Corporation 4800 Concord Road Dr. John M. Barry York, South Carolina 29745 Mecklenberg County Department of Environmental ]

Protection p 700 N. Tryon Street .

Charlotte. Nodh Carolina 28202

I REQUEST FOP, ADDITIONAL INFORMATION MCGUlRE GRINNELL SNUBBER ,

1, in its letter dated August 28,1997, to the Nuclear Regulatory Commission (NRC), the licensee stated that "The[Grinnell) snubbers are completely mechanical in nature and

contain no electro-mechanical components," and, "The review of the regulatory d: *nts and the current license basis reveals that completely mechanical equipment doe 1, i have specific regulatory required methods of demonstrating qualification to environmental conditions."

It should be noted that the NRC does include the environmental qualification of mechanical equipment under General Design Criterion 4, " Environmental and Dynamic Effects Design Bases," which states, in part, that " Structures, systems, and componen% important to safety shall be designed to accommodate the effects of and to be compatible with the environmental conditions associated with normal operation, maintenance, testing, and postulated accidents," Therefore, the staff requests that you provide the technicaljustification for how all of the safety-related snubbers at McGuire comply with General Design Criterion 4.

2. In its letter dated August 28,1997, to the NRC, the licensee stated that, 'Further irview by Duke Energy and Grinnell have not verified whether or not original temperature qualification testing was performed for the snubbers. Grinnell has not stated conclusively whether or not such testing was performed, but has not produced records of past testing."

Chapter 10 to the Code of Federal Reaulations (CFR) Part 50, Appendix B, Criterion

- XVil, " Quality Assurance Records," states, in part, that, " Sufficient records shall be maintained to fumish evidence of activities affecting quality. The records shall also include closely-related data such as qualifications of equipment. Records shall be identifiable and retrievable." Therefore, how do all of the safety-related snubbers at McGuire comply with 10 CFR Part 50, Appendix B, Criterion XVil?

3. It is the staffs understanding that there are approximately 150 Grinnell snubbers that .

were purchased in August 1996 and installed for the Steam Generator (SG)

Replacement Project that did not meet the purchase specifications for environmental conditions. Specifically, the specifications for temperature (350 degrees F) and radiation (2 x 10E8 rads) were not met.

How do the remaining safety-related snubbers (inside containment) that are currently insta!!ed at McGuire differ from those that were installed for the SG Replacement Project? What are the temperature limits and radiation limits on the purchase specifications for the remaining installed safety rstated snubbers? Do these remaining snubbers meet their purchsse specifications? Are there any qualifying data to demonstrate the environmental qualifications (EQ) for the remaining snubbers? Do the as-installed specific ttions for the remaining safety-related snubbers differ from the design basis documents? If so, was a 10 CFR 50.59, " Changes, Tests, and Experiments," performed to justify the change to the design basis? Moreover, do the Enclosure

a. ..

2 EQ requirements for the snubbers purchased in 1996 differ from the requirements used j for those remaining saubbers inside containment? If yes, provide the basis to justify why different EQ requirements are used?.

4. As discussed in Question 2 of the staffs RAI dated June 16,1997, in its assessment of the snubbers operability during a postulated main steamline break (MSLB) event. the licensee relies upon a time lag between the peak dynamic load due to pipe rupture and -

o the peak containment temperature transient for the double-ended steam lir.e break such that the temperature peaks after the pipe rupture dynamic load is over. Howaver, Figure 6 24 of the McGuire Final Safety Analysis Report shows that for a 1.4 ft8 double-ended MSLB, the temperature in the lower compartment peaks at 315 dogmes F immediately after the postulated MSLB and eventually drops and steadies at about 250 degrees F indefinitely. It is not clear how the licensee justifies the time lag between the peak pipe rupture dynamic load transient and the peak temperature transient. The licensee is requesied to provide's detailed comparison of these two trans'ents and to assess the snubber's operability accordingly.

5. The licensee's letter dated August 28,1997, indicated that the two snubbers that were recently tested were manufactured in 1W8 by Grinnell. However, as noted in Question 3 of this RAI, those Grinnell snubbers that did not meet the McGuire purchase specifications were purchased in August 1996. It does not appear that the tested snubbera were from the population that did not meet the purchase specifications.

The licensee is requested to provide an explanation of testing the 1978 anubbers in lieu of tne affected snubbers that were purchased in August 19967

6. Explain in detail how the test conditions as described in Section 3 of the Grinnell's test report (attachment 2 of the licensee's August 28,1997, latter) simulate the postulated MSLB accident conditions for McGuire. The explanation should include the length of time that the snubber is required to operate for the dynamic load transient and for the associated containment temperature transient.

7. li is noted in a letter dated August 23,1996, that Grinnell informed the licensee that for the snubbers purchased in 1996, it has no qualifying data to subelantiate the environmental conditions lishd in the licensee's specifications. It also stated thd the s reservoir material will exponence significant distortion at temperatures above 250 degrees F, and it will not maintain a proper seal. However, in its August 28,1997 letter, the licensee stated that the vendor assured the licensee that the snubbers are designed by acceptable engineering methods to be compatible with post accident environmental conditions. The licensee further stated that it concurs with the vendor. Based on the vendor's statement in its letter to the licensee dated August 23,1996, and the review of the information provided to the staff by the licensee, the staff determined that the licensee has not provided adequate technical basis to justify the above conclusion statements as stated in its Augus; 28,1997, letter. The licensee is requested to provide further details to justify the above conclusion statements.

Furthermore, it is noted that Section 6, Test Results, of Grinnell's report stated that no restriction of motion was encountered with either snubber. It is also noted that during

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1 3

this recent snubber ts st, the snubbers were heated up to 350 degrees F for 10 minutes.

However, as discussed in the above paragraph, Grinnell has previously stated that the snubbers will experience severe distortion and fluid leakage for temperatures above 250 degrees F. Were any leaks noted during this recent snubber testing? The licensee is requested to provide more details of the test results. The details should include the -

results of the visual examination of the snubbers after the tests and the identification of observed damage (e.g., seal leakage, reservoir distortion, etc.).

Finally, based on Grinnelfs statements in the August 23,1996, letter and observed snubber damage during testing, the licensee is requested to explain the basis for concluding that the observed damage would not affect the snubber's functionality of restraining piping movements during a seismic event and to discuss the cons:squential effect on the operability of the affected safety related systems.

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