ML20045B293
| ML20045B293 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom, Limerick  |
| Issue date: | 06/09/1993 |
| From: | Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-93-002, IEB-93-2, NUDOCS 9306170151 | |
| Download: ML20045B293 (4) | |
Text
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NRCB No. 93-02 v
PHILADELPHIA ELECTRIC COMPANY 10CFR50.54(f).
NUCLEAR GROUP HEADQUARTERS 955-65 CHESTERBROOK BLVD.
WAYNE, PA 19087-5691 (215) M044X10 June 9, 1993 Docket Nos. 50-277 i
SWlOf4 SUPPORT DEPARTMEtJT 50-278 50-352 50-353 License Nos. DPR-44 DPR-56 NPF-39 NPF-85 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Subject:
Peach Bottom Atomic Power Station, Units 2 and 3 Limerick Generating Station, Units 1 and 2 Response to NRC Bulletin No. 93-02, " Debris Plugging of Emergency Core Cooling Suction Strainers" Gentlemen:
This letter provides Philadelphia Electric Company's (PEco's) response to NRC Bulletin (NRCB) No. 93-02, " Debris Plugging of Emergency Core Cooling Suction Strainers," for Peach Bottom Atomic Power Station (PBAPS), Units 2 and 3, and Limerick Generating Station (LGS), Units 1 and 2. This letter is being submitted under affirmation in accordance with 10CFR50.54(f), and the required affidavit is enclosed.
NRCB No. 93-02 was issued on May 11, 1993, to_ notify licensees of a previously unrecognized contributor to the potential loss of net positive suction head (NPSH) for Emergency Core Cooling Systems (ECCS) during the recirculation phase of a loss-of-coolant accident (LOCA).
Specifically, this Bulletin identifies concerns that fibrous material in the primary containment suppression pool can accumulate and capture other debris and clog ECCS pump suction strainers which may cause a rapid loss of NPSH for the ECCS pumps when they are needed to perform their intended function.
The NRC requested that licensees identify fibrous air filters or other tempcrary sources of fibrous material, not designed to withstand a LOCA, which are installed or temporarily stored in the primary containment.
In addition, the NRC requested that we take any compensatory a
measures that may be required to ensure the functional capability of the ECCS and respond within 30 days of the date of this Bulletin identifying the actions the licensee has taken or proposes to take. Each reporting requirement is restated below, followed by PEco's response for PBAPS, Units 2 and 3, and LGS, Units.1 and 2.
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U.S. Nuclear Regulatory Commission June 9, i993 i
4 NRCB No. 93-02 Page 2 j
Reoortina Reauirement 1 Within 30 days of the date of this Bulletin, a written response stating whether the actions requested above have been or will be performed.
If i
the use of such material is identified, this written response shall also-include the locations and quantity of use, and immediate compensatory measures taken, and the current schedule for removal of the material.
ResDonse The primary containment drywell ventilation systems at PBAPS and LGS do not utilize any permanent or temporary filter devices.
Since no permanent or temporary filters are used in the installed drywell ventilation systems, the possibility of having fibrous air filter material transported to the suppression pool following a LOCA does not exist.
Plant pr acedures at both PBAPS and LGS require an inspection of the drywell and suppression pool air space and suppression pool water surface following outages when there is access to the primary containment, to ensure that debris, material, and equipment (e.g., portable High Efficiency Particulate Air (HEPA) filters) temporarily used to support outage activities is removed prior to plant startup.
No temporary fibrous material is stored in the primary containment during power operations.
In addition, these procedures contain steps to check for loose or damaged insulation that is installed on piping systems in the drywell.
The only fibrous material utilized in the LGS and PBAPS primary containments is comprised of permanently installed insulating material.
The insulating material used in the drywells at LGS and PBAPS is installed on piping systems and primarily consists of either mirror insulation or low-density, soft fiberglass insulation (i.e., "Nukon" blankets) with woven fiberglass covers and/or stainless steel jackets.
These insulating materials are described in the appropriate sections of the Updated Final Safety Analysis Reports for PBAPS, Units 2 and 3, and LGS, Units 1 and 2.
Reportina Reauirement 2 Within 30 days of completion of the requested actions, a report confirming completion.
Response
PECo considers that the design features and procedural requirements that currently exist at PBAPS and LGS, as described above, are adequate to prevent the transport of fibrous material debris to the suppression pool and thereby maintain the required NPSH for the ECCS (e.g., Residual Heat Removal. (RHR) and Core Spray (CS) systems) pumps in the event of a LOCA.
No additional actions are being considered at this time, and therefore, a 30 day report providing confirmation that the requested actions have been completed is not necessary.
Reportina Reauirement 3 l
If an addressee proposes not to take the actions requested in this bulletin, provide to the NRC staff, within 30 days of the date of this l
bulletin, your proposed alternative course of action and a justification for any deviations form the requested actions.
U.S. Nuclear Regulatory Commission June 9, 1993 NRCB No. 93-02 Page 3 ResDonse No fibrous air filters or other temporary sources of fibrous material are installed or stored in the LGS and PBAPS primary containments. As stated above, PECo considers the design features and procedural requirements that exist at PBAPS and LGS adequate to preclude blockage of the ECCS pump suction strainers due to fibrous material debris, and therefore, no additional actions are planned.
t As requested in NRC Bulletin 93-02, PECo is providing information concerning the time and costs associated with responding to this Bulletin.
Approximately 30 man-hours, at an estimated cost of $1200, was expended in preparing our response to NRCB No. 93-02. This estimate is based entirely on our efforts to prepare and review this response, since it was not necessary for PEco to implement any compensatory measures, as described above, as a result of the Bulletin.
If you have any questions or require additional information, please do not hesitate to contact us.
Very truly yours, fe G. A. Hunger, Jr.
Director Licensing Section Enclosure cc:
T. T. Martin, Administrator, Region I, USNRC (w/ enclosure)
USNRC, Senior Resident Inspector, PBAPS (w/ enclosure)
N. S. Perry, Senior Resident inspector, LGS (w/ enclosure)
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COMMONWEALTH OF PENNSYLVANIA COUNTY OF CHESTER G. R. Rainey, being first duly sworn, deposes and says:
That he is Vice President of Philadelphia Electric Company; that he has read the foregoing response to NRC Bulletin No. 93-02, " Debris Plugging of Emergency Core Cooling Suction Strainers," for Peach Bottom Atomic Power Station, Units 2 and 3, and Limerick Generating Station, Units 1 and 2, and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
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