ML17059B094
| ML17059B094 | |
| Person / Time | |
|---|---|
| Site: | 05000200, Nine Mile Point |
| Issue date: | 03/28/1996 |
| From: | Hood D NRC (Affiliation Not Assigned) |
| To: | Sylvia B NIAGARA MOHAWK POWER CORP. |
| References | |
| IEB-95-002, IEB-95-2, TAC-M93867, NUDOCS 9604030064 | |
| Download: ML17059B094 (10) | |
Text
Mr.
B. Ralph Sylvia (la~ 28, 1996 Executive Vice Presid~
Nuclear Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION NINE MILE POINT NUCLEAR STATION UNIT NO.
1 (TAC NO. M93867)
Dear Mr. Sylvia:
On November 16,
- 1995, Niagara Mohawk Power Corporation (NMPC) responded to NRC Bulletin 95-02, "Unexpected Clogging of a Residual Heat Removal (RHR)
Pump Strainer While Operating in Suppression Pool Cooling Mode" for Nine Mile Point Nuclear Station Unit No.
1.
The NRC staff is reviewing this response and finds that additional information requested in the enclosure is needed.
Please provide your response by April 26,
- 1996, so that we can complete our review consistent with the current schedule.
If your have questions about the enclosure or are unable to meet the requested response
- date, please call me at (301) 415-3049.
This requirement affects nine or fewer respondents and, therefore, is not subject to the Office of Management and Budget Review under P.L.96-511.
Sincerely, ORIGINAL SIGNED BY:
Docket No. 50-220
Enclosure:
Request For Additional Information cc w/encl:
See next page Darl S.
Hood, Senior Project Manager Project Directorate I-l Division of Reactor Projects I/II Office of Nuclear Reactor Regulation DISTRIBUTION:
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t UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 205554001 March 28, 1996 Mr. B. Ralph Sylvia Executive Vice President, Nuclear Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - NINE MILE POINT NUCLEAR STATION UNIT NO.
1 (TAC NO. M93867)
Dear Mr. Sylvia:
On November 16,
- 1995, Niagara Mohawk Power Corporation (NMPC) responded to NRC Bulletin 95-02, "Unexpected Clogging of a Residual Heat Removal (RHR)
Pump Strainer While Operating in Suppression Pool Cooling Mode" for Nine Mile Point Nuclear Station Unit No.
1.
The NRC staff is reviewing this response and finds that additional information requested in the enclosure is needed.
Please provide your response by April 26,
- 1996, so that we can complete our review consistent with the current schedule.
If your have questions about the enclosure or are unable to meet the requested response
- date, please call me at (301) 415-3049.
This requirement affects nine or fewer respondents and, therefore, is not subject to the Office of Management and Budget Review under P.L.96-511.
Sincerely, Docket No. 50-220 Darl S.
Hood, Senior Project Manager Project Director ate I-1 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation
Enclosure:
Request For Additional Information cc w/encl:
See next page
B. Ralph Sylvia Niagara Mohawk Power Corporation Nine Hile Point Nuclear Station Unit No.
1 CC:
Hark J. Wetterhahn, Esquire Winston 5 Strawn 1400 L Street, NW Washington, DC 20005-3502 Supervisor Town of Scriba Route 8, Box 382
- Oswego, NY 13126 Mr. Richard B. Abbott Vice President - Nuclear Generation Niagara Mohawk Power Corporation Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Resident Inspector U.S. Nuclear Regulatory Commission P.O.
Box 126
- Lycoming, NY 13093 Gary D. Wilson, Esquire Niagara Mohawk Power Corporation 300 Erie Boulevard West
- Syracuse, NY 13202 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Hr. F. William Valentino, President New York State
- Energy, Research, and Devel'opment Authority 2 Rockefeller Plaza
- Albany, NY 12223-1253 Hr. Norman L. Rademacher Unit 1 Plant Manager Nine Mile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Hs. Denise J. Wolniak Manager Licensing Niagara Mohawk Power Corporation Nine Nile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093 Charles Donaldson, Esquire Assistant Attorney General New York Department of Law 120 Broadway New York, NY 10271 Mr. Paul D.
Eddy State of New York Department of Public Service Power Division, System Operations 3 Empire State Plaza
- Albany, NY 12223 Hr. Martin J. HcCormick, Jr.
Vice President Nuclear Safety Assessment and Support Niagara Mohawk Power Corporation Nine Hile Point Nuclear Station P.O.
Box 63
- Lycoming, NY 13093
(s ~w C
I
ST FOR ADDITIO AL INFORMATION OI T NUC AR ST IO U
T O.
The NRC staff has the following questions and requests with respect to your response of November 16, 1995, to NRC Bulletin 95-02, "Unexpected Clogging of a Residual Heat Removal (RHR)
Pump Strainer While Operating in Suppression Pool Cooling Mode":
Why did you not clean the Nine Mile Point Unit 1
(NMPl) suppression pool (torus) during the last outage?
We note that the pool for NMP2 was cleaned during its last refueling outage which occurred just after the outage (i.e.,
about the same general time frame) for NMP1.
In view of the heightened sensitivity to this RHR clogging potential and the numerous generic communications on this subject since the Bar sebhck and Perry events, have you taken any other significant measures to protect the operability of the emergency core cooling system (ECCS)2 2.
3.
4, 5.
Why have you not cleaned the NMPl suppression pool since 19812 Did you ever evaluate the potential impact of not cleaning the pool for such a
long time2 If so,
- when, and what were your findings2 Please describe the considerations given to, and limitations associated with, performing a multi-pump test to verify the operability of the ECCS as requested in the bulletin.
(Are you able to conduct a multiple pump test at power to demonstrate operability, and if not, why not?
We understand that the strainers are accessible for inspection at power, and do not fully understand your limitations with respect to multiple pump tests).
Given your plant limitations, is it possible to perform a multi-pump test using one train of core spray and one train of containment spray2 If not, provide the basis for your conclusion that such a test is not needed to assure that the pool is sufficiently free of debris to allow continued operation until the torus pool cleaning scheduled for the next refueling outage.
During anticipated transients (such as a stuck open safety relief valve) or other abnormal
- events, would the plant operators ever be required by procedure to run more than one loop of RHR in torus cooling mode?
Have you conducted any underwater inspections of the suppression pool floor or ECCS inlet piping since the last pool cleaning2 If so, what were the findings?
What were the results of your downcomer and ringheader inspections?
You appear to be relying upon the results of three samples taken in March 1995 for your statement that there is no evidence of fibrous material in the torus.
We are concerned that three random samples might miss fibrous material lying on the pool floor or located in an area other than that where the sample was taken.
What is Enclosure
I
the possibility that other non-fibrous material is present in the pool that would not likely be detected by a sample (e.g., plastic bags, duct tape, etc.)?
You indicate your belief that operation of more than one loop of low-pressure core spray would not significantly increase turbulence and mixing in the pool.
Would the turbulence created by such operation be representative of turbulence expected during an abnormal operating condition or transient?
In what direction are the return lines from low-pressure coolant injection to the suppression pool oriented (e.g.,
do they discharge directly towards the center of the torus, or do they direct flow axially around the torus)2 What is the basis for your confidence that the Unit 1 pool is sufficiently clean?
(We note that the Perry staff also thought their pool was clean, but found otherwise during a later test of the pumps.
Limerick staff also found additional debris accumulation when they conducted a test after cleaning.)
Have there been any significant changes to your Foreign Haterial Exclusion program since the pool was cleaned in 19812 What was the potential for debris introduction into the torus prior to any changes that were made2 To what extent were the RHR pumps operated in the torus cooling mode during the last operating cycle?
Have you had occasion to run more than one pump at a time?
Describe the instrumentation that alarms in the control room upon'high differential pressure.
How does the operator know what the actual pressure differential is?
What actions would the operator take upon receiving an indication that the strainers were clogging, and at what point would the operator take these actions?
Can the strainers be cleaned during an abnormal event or transient?
Please provide a clear statement of your intention to clean the pool during the next available outage (planned or unplanned) of sufficient duration.
This statement should include your definition of sufficient duration.
C