ML20247J749

Requests Exemption from 10CFR50.44(c)(3)(ii)(B) to Power Hydrogen Recombiner Containment Isolation Valves as Stated

ML20247J749
Person / Time
Site:	Limerick
Issue date:	05/23/1989
From:	Hunger G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 8906010123
Download: ML20247J749 (5)

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, l-L PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHIA A. PA 19101 (215) 8414ooo May 23, 1989 10CFR50.12.

Docket Nos. 50-352 50-353 License No. NPF-39 Construction Permit-No. CPPR-107 U. S. Nuclear Regulatory Conmission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

- Limerick Generating Station, Units 1 & 2 Request for Exemption from 10CFR50.44 Gentlemen:

In accordance with 10CFR50.12(a) Philadelphia Electric Company requests an exemption from 10CFR50.44(cX3XIIXB1 to power the hydrogen reconbiner containment isolation valves from the same power supply division as their associated recombiners to provide for gieater ~

recombiner reliability. The attachment;to this letter provides the specific Justifications in accordance with the requirements of 10CFR50.12(a).

If you have any questions, please do not hesitate to contact us.

Ver truly yours,

. h. of .

G. A. Hunger, Jr.

Director, Licensing Section Nuclear Support Division CWW/nm/05118901 Attachment hC Copy to: R. J. Clark, USNRC Project Manager W. T. Russell, Administrator, Region I, USNRC tg T. J. Vsenny, USNRC Senior Resident Inspector, LGS 8906010123 890523 PDR ADOCK 05000352 P PDC

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l bec: C. A, McNeill, Jr. S26-1 S. J. Kowalski S25-1 J. S. Kemper S25 E. J. Bradley S23-1 E. P. Fogarty S7-1 J. M. Madara, Jr. 57-1 G. A. Hunger, Jr. S7-1 D. P. Helker S7-1 R. M. Krich S7-1 D. B. Fetters N4-1 L. B. Pyrih N2-1 A. J. Marie N2-1 H. D. Honan N2-1 R. J. Scholz N2-1 G. M. Leitch LGS MC 200 P. J. Duca, Jr. LGS MC AS-1 C. R. Endriss LGS MC A2-1 A. S. MacAlnsh LGS MC 583-4 M. S. Iyer BPC/SF DAC NG-8 i

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ATTACHMENT REQUEST FOR EXEMPTION FROM THE REQUIREMENTS OF 10CFR50.44CcX3XIIXB)

Exemption Requested 10CFR50.44 provides standards fcr combustible gas control systems in light-water-cooled power reactors. Section 50.44(cX3XilXB) states in part that containment penetrations used for external recombiners must be " designed against postulated single failures both for containment isolation purposes and for operation of the external recorrbiners".

Philadelphia Electric Company requests an exemption from 10CFR50.44CcX3Xi tXB) to permit the power supplies for the hydregen recombiner containment isolation valves to be from the same electrical power division as their associated recombiner- to provide for greater recombiner reliability.

Justification for Requested Exemption The requested exemption may be granted by the NRC under 10CFR50.12(a) provided that the exemptI7n is: I) authorized by law, II) will not present an undue risk to the pubile health and safety, III) is consistent with the cormon defense and security, and IV) Justified by the presence of special circumstances of the type Identified in Section 50.12(aX2).

I. The Requested Exemption And The Activities Which Would B_e Allowed Thereunder Are Authorized By Law If the criteria established in 10CFR50.12(a) are satisfied and no other prohibition of law exists to preclude the activities which would be authorized by the requested exemption, then the Conmission is authorized by law to grant the exemption request. . Since, as demonstrated herein, the requested exemption meets the applicable criteria and there is no legal prohibition to its grant, the Conmission is authorized by law to grant the exemption.

. - o LGS Units 1 & 2 Docket Nos 50-352 50-353 Page 2 of 3 t

II. The Requested Exemption Will Not Present An Undue Risk To The Pubile Health And Safety For the reasons stated below and in Section IV, Special Circumstances, the requested exemption to power the recombiner containment isolation valves from ttw same power supply division as their associated recombiners does not present undue risk to the public health and safety. The affected valves and their associated reconbiners are listed below:

Unit 1 Inboard Valves Outboard Valves Recombiner A HV-57-161 (Inlet) FV-C-57-D0-101A (Inlet)

HV-57-162 Coutlet) HV-57-166 (Outlet)

Recombiner B HV-57-163 (Inlet) FV-C-57-00-101B (Inlet)

HV-57-164 (Outlet) HV-57-169 (Outlet)

Unlt 2 Inboard Valves Outboard Valves Recombiner A HV-57-261 (Inlet) FV-C-57-DD-201A (Inlet)

HV-57-262 Coutlet) HV-57-266 (outlet)

Recombiner B HV-57-263 (Inlet) FV-C-57-D0-201B (Inlet)

HV-57-264 (Outlet) HV-57-269 (outlet)

Powering these isolation valves from the same electrical division their associated recombiner is acceptable for the following reasons:

1) The valves are all normally closed and are not required to be opened to permit recombiner operation until approximately 39 hours4.513889e-4 days <br />0.0108 hours <br />6.448413e-5 weeks <br />1.48395e-5 months <br /> post-LOCA (Reference FSAR Section 6.2.5.3).

2) The recombiner system is designed as a closed system outside containment as described in FSAR Section 6.2.4.3.1.3.2.3.

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LGS Units 1 S 2 Docket Nos 50-352 50-353 Page 3 of 3

3. System reliability from the same power supply is discussed in FSAR Section 6.2.4.3.1.3.2.3. A failure of only.one electrical power division will disable the recombiner subsystem. If diverse power supplles were provided, one of two power supply failures tould disable the reccmbiner subsystem.

III. The Requested Exemption is Consistent With The Camion Defense And Security The cormon defense and security are not endangered by this exemption request. Only the potential inpact on public health and safety is at issue and has been determined to be inconsequential.

IV. Special Circumstances The regulu W requires that penetrations used for external recombiners ba " designed against postulated single failures both for containment isolation purposes and for operation of the external recenti ners". Separation of the power supplies for the containment isolation valves would decrease the reliability of the subsystem in that failure of either of the power supplies would disable the recombiner subsystem.

Therefore, granting this exemption to allow a conmon power supply would result in a benefit to public health and safety.

Further, the acceptability of the Limerick design has been doctmented in FSAR Section 6.2.4.3.1.3.2.3 and in the Conmission's Safety Evaluation Report issued with Amendment No. 13 to Facility Operating License NPF-39 (Limerick Unit 1).

Conclusion Based on the Justification above, Philadelphia Electric Company requests an exemption under 10CFR50.12(a) to 10CFR50.44CCX3XIiXB) to permit powering the recombiner containment isolation valves from the same power supply division as their associated recombiners. The

-Justifications provided represent several of the special ciretmstance requirements of 10CFR50.12(aX2) necessary in order to grant the requested exemption. Granting the exemption would result in an overall benefit to the public health and safety by maximizing reliability of the hydrogen recombiner subsystems CW/nm/051189 a;

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