ML20064N938

Forwards Responses to Resolve Power Sys Branch Open Item 33, Compliance W/Reg Guide 1.63, of FSAR Section 8

ML20064N938
Person / Time
Site:	Seabrook
Issue date:	09/09/1982
From:	Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO.
To:	Miraglia F Office of Nuclear Reactor Regulation
Shared Package
ML20064N942	List: ML20064N938 ML20064N955
References
SBN-322, NUDOCS 8209130041
Download: ML20064N938 (5)

Text

SEMOOK STATION PUBLIC SERVICE Engineedng Of6ce:

Companyof NewHampshire 1671 Worcester Road Framingham, Mossachusetts 01701 (617) - 872- 8100 September 9, 1982 SBN -322 TF B7.1.2 United States Nuclear Regulatory Commision .

Washing ton, D.C. 20555 Attention: Mr. Frank J. Miraglia, Chief Licensing Branch No. 3 Division of Licensing

References:

(a) Construction Permit CPPR-135 and CPPR-136, Docket Numbers 50-443 and 50-444 (b) PSNil Letter dated July 2, 1982, "FSAR Section 8, Open Item List - Power Systems Branch (Electrical)"J. DeVincentis to F. Miraglia

Subject:

FSAR Section 8, Open Item List - Power System Branch (Electrical)

Dear Sir:

As promised in our July 2, 1982 letter (Reference b), we are providing written responses to resolve the remaining concerns of Open Item 33

" Compliance with Regulatory Guide 1.63".

Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY E '4, h ljc , y y;,

J. Devincentis f[ u Project Manager GTS/kac Attachment 8209130041 820909 PDR ADOCK 05000443 A PDR

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OPEN ITEM 33 '

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Compliance with Regulatory Guide 1.63

RESPONSE

This item was discussed during a telephone conversation on June 2,1982, and again during the June 18, 1982 meeting.

DISPOSITION The majority of the concerns were resolved during these discussions. Written 1 responses are provided herewith for the following remaining concerns:

! 1. Equipment inside containment that is infrequently used (cranes, refueling

• I machines, etc.) and does not have redundant penetration protection will have to be under Technical Specification limitations if credit is to be l given in having the feeder breaker locked open. If not, then redundant protection will have to be provided.

2. Further details on low-energy circuits inside containment not provided with redundant protection.

3. Details of physical and electrical separation between the primary and

back-up protective devices.

1 The attached revised FSAR pages and RAI 430.54 provide information which l addresses the above concerns. For information only, we are also providing sample pages of the Technical Specifications indicating how we are proposing to address the concern on infrequently used equipment inside containment.

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. SB 1 & 2 FSAR i

7. Special 480 Volt Circuits l (a) Protection of Containment Electrical Penetrations The Class lE and noa-Class lE 480 volt unit substations, 460 volt motor control centers and the distribution panels which feed loads inside the containment are all qualified to meet Class lE

, requirements and are located in Seismic Category I structures. 460 volt loads inside the containment are fed from distribution equipment with special provisions to satisfy the requirements of Regulatory Guide 1.63 for containment electrical penetration protection. These provisions are outlined below.

1 460 volt loads inside containment which are fed from motor control centers or distribution panels are provided with one of the following special arrangements to insure that the penetration integrity is maintained.

(1) Circuits of motors 5 hp and less are provided with two identical combination starters. Both units are located in the same compartment of the MCC. See Figure 8.3-49 for typical coordination curves. ,

(2) Circuits of motors greater than 5 hp are provided with a thermal magnetic breaker in series with a combination starter. Both the r breaker and the combination starter are located in the same compartment of the MCC. See Figure 8.3-48 for typical coordination curves.

i (3) Feeder circuits, including the pressurizer heater circuits, are l provided with two identical thermal magnetic breakers. Both breakers are located in the same compartment of the MCC or panel.

The motor control centers containing these special protective devices are located in the Control Building switchgear area, with the one exception, the panels for the pressurizer heater circuits are located in the electrical penetration area outside the containment. Both the primary and the backup protective devices are qualified lE devices.

There are no high or moderate energy lines in the above areas, therefore, only f aults within the electrical devices could conceivably damage these protective devices. If a protective device fails catastrophically while clearing a short circuit, the second protective device may possibly be affected because of its proximity.

However, in this instance, no penetration damage can occur because all short circuit current flow will be diverted to the new f ault l

located at the protective device. Therefore, there is no conceivable l electrical failure that could prevent both the protective devices from operating and at the same time allow the fault current to flow through the penetration.

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SB 1 & 2 FSAR 460 volt loads inside the containment, which are fed directly from the 480 volt unit substations, satisfy the requirements of Regulatory Guide 1.63 by utilizing the load breaker as primary protection and the unit substation incoming feeder breaker as backup protection.

See Figure 8.3-48 for an example.

460 volt loads inside the containment which are normally used only during shutdown (e.g., cranes, refueling machines, welding receptacles, etc.) are not provided with redundant protection because their circuits are de-energized and padlocked at the unit substation or motor control center during normal plant operation. Verification of the circuits being de-energized is part of the Technical Specifications. Though some of these circuits may be required for brief durations during plant operation such as prior to or after refueling outages, lack of redundant protection is justified because of the very limited usage in this mode and the fact that such usage will be under Technical Specification requirements.

Control circuits powered f rom 120 V ac or 125 V de distribution panels have dual protective devices (circuit breakers and/or fuses) to provide penetration protection in accordance with Regulatory Guide 1.63.

Control circuits powered from limited capacity power sources such as control power transformers (maximum capacity 150 VA) and instrumentation circuits do not require dual protection because the short circuit versus time capacity of their power sources is within the penetration capabilities.

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Revised September 1982 430.54 Section 8.3.1.2.b.4 of the FSAR indicates that instrumentation and l low energy circuits are not provided with redundant overload protection devices. Define low energy circuits and justify

! non-compliance with the guidelines of Regulatory Guide 1.63.

l RESPONSE: Low energy circuits are those energized by devices that are inherently energy self-limiting (e.g., control transformers or instrumentation current / voltage loop power supplies, etc.)

Regulatory Guide 1.63 is satisfied because a short circuit would result in an energy level which is sufficiently low as to preclude l

damage to the electrical penetration seal.

For more information on low energy circuits, refer to Section 8.3.1.lc (7) of the FSAR.

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