ML20247R929

Proposed Tech Spec Table 3.6-1, Secondary Containment Bypass Leakage Paths

ML20247R929
Person / Time
Site:	Seabrook
Issue date:	09/21/1989
From:	PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:
Shared Package
ML20247R922	List: ML20247R916 ML20247R929
References
NYN-89116, NUDOCS 8910020108
Download: ML20247R929 (4)

Text

,,_.;-- -

i

.. . 4 * .

New Hampshire Yankee September 21. 1989 l 1

i i

1 l

i Enclosure 1 to NYN-89116 .

PROPOSED TECHNICAL SPECIFICATION CHANGE <

l 1

j I

i i

I a

1 a

l I

i 1

1 I

l l

l l

1 i

8910020108 890921 PDR I

P ADOCK 05000443 PDC l

l^ j u_____ _ _ _ _ _ _ _ _ . . - _ _ _ _

a TABLE 3.6-1 (Continued)

SECONDARY CONTAINMENT BYPASS LEAKAGE PATHS PENETRATION NO. FUNCTION RELEASE LOCATION

- X-378- Chemical and Volume Control Primary Auxiliary Building (Excess Letdown)

X-38A/76A- Fire Protection . Fire Watar Pumphouse/ Fire Water Tanks X-38B/76B Combustible Gas Control Main Steam and Feedwater Pipe Chase X-39' Spent Fuel Pool Cooling and Fuel Storage Building Cleanup X-40A- Nitrogen Gas (Low Pressure) . Primary Auxiliary Building X-408- PRT Sample Primary Auxiliary Building

- X-62 Fuel Transfer Tube Fuel Storage Building

.~

X-67 Fervice Air Main Steam and Feedwater (-' '

+ Pipe Chase -

X-7 W 740 Leak Detection Main Steam and Feedwater Pipe Chase HVAC-1 Containment Air Purge Primary Auxiliary Building HVAC-2 Containment Air Purge Primary Auxiliary Building N.A. Equipment Hatch Outside N. A. Personnel Haten Main Steam and Feedwater Pipe Chase

' X-72/75 Combustible Gas Control Main Steam and Feedwater Pipe Chase

- x,68 Instrument Air Main Steam and Feedwater Pipe Chase I f s.

f SEABROOK - UNIT 1 3/4 6-6

_ _ - _ _ _ a

, .i

[ New Hampshire Yankee September 21, 1989 Enclosure 2 to NYN-89116

Background:

The Containment Building Compressed Air System supplies the instrument air requirements of pneumatic instruments and actuators within the Containment Building. Air for the system is supplied by two compressors located inside the Containment Building. One of the major components that relies on the Containment Building Compressed Air system is the Primary Component Cooling Water (PCCW) System containment isolation valves. The operability of the PCCW System is essential to the operation of the Reactor Coolant Pumps. Loss of the Containment Compressed Air System will ultimately cause a forced plant shutdown.

Description of Proposed Channes:

To preclude the potential of a forced plant shutdowt as a result of loss of the Containment Building Compressed Air System, New Hampshire Yankee (NHY) proposes that a backup air supply be connected to the Containment Building Compressed Air System. The back-up air supply would be a cross-connection between the Plant Instrument Air System and the Containment Air System. The cross-connect would enter the Containment Building thru an existing Containment penetration, X-68. The penetration will be added to Technical Specification Table 3.6-1 " Secondary Containment Bypass Leakage Paths".

The propoced change would be implemented in two phases. The first phase is scheduled for completion prior to commercial operation and would include the installation of the cross-connect piping from the Plant Instrument Air System to the Containment Compressed Air System. The piping isolation design will meet 10 CFR 50, Appendix A, General Design Criteria 56, " Primary Containment Isolation" by utilizing a fail-closed air operated valve outside Containment and a check valve inside Containment. The air operated valve's automatic open/close function will be disarmed and the valve will be administratively controlled in the locked closed position for Modes 1-4. The second phase of this change will provide the instrumentation and electrical changes required to make the cross-connect operate automatically with Containment Air System low pressure and assure post-accident isolation. This phase is scheduled to be implemented prior to completion of the first refueling outage.

1

.. . .s New Hampshire Yankee September 21, 1989 Safety Evaluation of Proposed Changes New Hampshire Yankee has reviewed the prcposed changes utilizing the criteria specified in 10 CFR 50.92 and has determined that the proposed change would not

1. Involve a significant increase in the probability of consequences of any accident previously evaluated. The activation of a previous spare piping penetration to the Containment will allow utilization of the Plant Instrument Air System to backup the Containment Building Compressed Air System during Modes 5 and 6. The Containment Building Compressed Air System is non-safety related and not is relied upon for safe shutdown. The new penetration piping is designed to Quality Group B standards and is subject to testing per 10 CFR 50, Appendix J. The activation of this penetration will not effect the existing offsite dosage analysis since the analysis already assumes the maximum possible bypass leakage. The total containment integrated leakage, as well as local leakage rates, will remain within 10 CFR 50, Appendix J, limits. This cross-connect will not be used during Modes 1-4, therefore, incoming instrument air will not affect containment peak pressure.

2. Create the possibility of a new or different kind of accident from any previously evaluated. The additional Type 'C" penetrations maximum leakage in conjunction with the combined leakage of the existing Type "B and "C" penetrations will not exceed the total leakage allowed by 10 CFR 50 Appendix J for bounding radiation doses to within the dose guidelines of 10 CFR Part 100 during accident conditions.

3. Involve a significant reduction in a margin of safety. The bases for the Technical Specifications indicate that allowable leakages will be consistent with assumptions made in the offsite dose analyses.

2

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ - _ - -