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ENCLOSURE 1 CHEMICAL ENGINEERING BRANCH 5AFETY EVALUATION REPORT INTERNAL CONDUIT SMOKE SEALS
_ INSTALLED AT APPENDIX R FIRE BARRIERS BO5 TON EDISON COMPANY PILGRIM NUCLEAR POWER STATION DOCKET NO. 50-293
1.0 INTRODUCTION
By letter dated February 3. 1988 (BEco 88-017), the licensee provided their criteria for installing smoke seals inside electrical conduits that pass through fire barriers from one fire area to another. The licensee provided these criteria to answt.r staff concerns discussed during a meeting betweea BEco and the staff on November 24, 1987.
2.0 EVALUATION Appendix R to 10 CFR 50 requires, among other things, that openings and other penetrations in rated fire barriers separating redundant trains of the safe shutdown systems and equipment shall be closed and sealed in a manner that maintains the required fire rating of the barrier. Specific requirements for fire barrier cable penetration seal qualification are contained in Section III.M of Appendix R to 10 CFR Part 50. Although Appendix R is silent as to requirements for sealing inside electrical conduits. BTP 9.5-1 does contain specific guidance concerning such seals in Section C.5.a.(3). That guidance provides that; "Openings inside conduit larger than 4 inches in diameter should be sealed at the fire barrier penetration. Openings inside conduit 4 inches or less in diameter should be sealed at the fire barrier unless the conduit extends at least 5 feet on each side of the fire barrier and is sealed either at both ends or at the fire barrier with noncombustible material to prevent the passage of smoke and hot gases.
Fire barrier penetrations that must maintain environmental isolation or pressure differentials should be qualified by test to maintain the barrier integrity under such conditions."
The criteria that the licensee has submitted confoms to the above guidance and subsequent guidance contained in Generic Letter 86-10.
The licensee's criteria for seals inside conduits specifies the following:
1.
Caly those bar.~ieri that separate redundant safe shutdown equipment l
will be evaluaNJ for smoke seals.
2.
Smoke seals are not required if automatic fire suppression is provided on both sides of a fire barrier.
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-2 3.
Smoke seals are not required on one side of a fire barrier if automatic fire suppression is provided on the other side.
4.
Smoke seals are not required if the passage of smoke does not jeopardize the operation of redundant safe shutdown equipment.
5.
Smoke seals are not required if the quantity, nature and location of combustibles are such that smoke generation is not a threat.
6.
Smoke seals are not required in conduits with a nominal size less than 3-inches in diameter if the conduit runs more than 10 linear feet before teminating.
7.
Conduits greater than 4-inches in diameter will be sealed internally with smoke tight fi*e sea'is at the barrier.
8.
Conduits 3 to 4-inches in diameter will be sealed internally at the barrier, or at the first opening on both sides of the barrier, or on one side of the bcrrier where it has been determined that only one smoke seal is necessary.
9.
Conduits with a nominal size less than 3-inches in diameter will be sealed on any side of the barrier where the conduit teminates at smoke damageable stfe shutdown equipment within a 10 foot linear run from the barrier.
If temination does not occur at damageable safe shutdown equipment within a 10 foot, the decision to seal the conduit shall be based on evaluation for Numbers 2 through 6 above.
- 10. Smoke seals are fabricated of non-combustible mate *ials and are essentially air tight so as to preclude passage of significant amounts of smoke.
In addition certain hardware components are acceptable in lieu of smoke seals. Acceptable hardware components include:
non-louvered and non-ventilated boxes; outlet boxes; keycardboxes(readers);
GAI tronics boxes.
The staff agrees with the licensee that smoke seals installed insida electrical conduits in accordance with the above criteria will give reasor'.ble assurance that smoke will not be transmitted from one fire area to another via electrical conduits in sufficient quantities to damage redundant safe shutdown systems or components.
3,0 CONCLUSION On the basis of the above Evaluation, we conclude that the internal conduit smoke seals installed by the licensee in accordance with the criteria described in their letter of February 3,1988 (BEco 88-017) are consistent with BTP 9.5-1 and, therefore, acceptable for the purposes dese.ribid above and in their letter.
ENCLOSURE 2 SALP INPUT FROM THE CHEMICAL ENGINEERING BRANCH FOR PII. GRIM NUCLEAR POWER STATION TAC NO. 99999 A.
Licensing Activities 1.
Management Involvement in Assuring Quality The criteria for installation of smoke seals inside electrical conduits to prevent smoke damage to redundant safe shutdown systems were fully described and comprehensive in scope. The quality of the licensee's letter was high and required no additional contacts by the staff Rating:
1 2.
Approach to Resolution of Technical Issues from a Safety Standpoint The approach to resolution of this issue was technically sound and fully satisfied NRC requirements and guidance.
Rating:
1 3.
Responsive to NRC Initiatives The licensee's letter on this issue was complete and required no questions',
or other follow-up from the staff Rating:
1 4.
Staffing (IncludingManagement)
Rating: N/A 5.
Reporting and Ar.alysis of Reportable Events Rating: N/A 6.
Training and Qualification Effectiveness Rating:
N/A 7.
Overall Rating for Licensing Activity in Functional Area Rating:
1 1
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b Docket No.: 50-?93
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Mr. Ralph E. Bird Senior Vice President - Nuclear Boston Edison Companv 800 Bovlston Street Poston, Massachusetts 02199 SU9 JECT:
URC REGION INSPECTION REPORT 87-39; RESOLUTION OF ITEM A PAGE 4 PILGRIM NUCLEAR POWEP STATION
REFERENCE:
TAC Number 66913 By letter dated December 8, 1987 (BECo 87-196), you orovided information and evaluation to resolve iten A on pace 4 of Region ! Inspection Report 87-39, which pertains to an exenstion granted from the reauirements of Appendix R to 10 CFR 50 to provide automatic suppression in the control room.
Approval of the exemption was based, in part, on a 3. hour fire rating for the ceiling / floor assembly between the Cable Spreading Room (CSR) and the Control Poom (CR). We have completed our review of the submittal and find that the present penetration seals are acceptable and that no uparading is required.
Therefore, we consider this iten and TAC number 66913 closed.
A copy of our Stfety Evaluation is also enclosed.
Sincerely, Daniel Mcdonald, Senior Project Manager Project Directorate I-3 Division of Reactor Projects I/II Enclosure cc w/ enclosure See next page O!STRIRUTION:
Docket File NRC & Local PORs PIM 4,a N RWessman BBoger MRushbrook CNeDomendw OGC EJordan JPartlow Tech Aranch r > 7W" ACRS (10) g-O O
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DATE :3/ /E8
- 3/ 4 88
- 3/81 88
- 3/M88
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ENCLOSURE 1 SAFETY EVALUATION LACK OF THREE-HOUR FIRE RATED PENETRATION SEALS IN CA8LE SPREADING ROOM CEILING / CONTROL ROOM FLOOR ASSEMBLY BOSTON EDISON COMPANY PILGRIM NUCLEAR POWER STATION DOCKET NO. 50-293
1.0 INTRODUCTION
By letter dated December 8,1987 (BEco 87-196), the licensee provided information and their evaluation to resolve Item A on page 4 of Region I Inspection Report 87-39 which certains to an exemption granted from the requirements of Appendix R to 10 CFR 50 to provide automatic suporession in the control room.
Approval of the exemption was based, in part, nn a 3-hour fire rating for the ceiling / floor assembly between the Cabie Spreading Room (CSR) and the Control Room (CR).
The December 8,1987 letter acknowledged that some penetration seals in the CSR ceiling /CR floor assembly do not meet the 3-hour fire rating, and that other seals are so located that the bottom surface cannot be inspected.
2.0 EVALUATION The licensee presented several technical points supporting their position that the existirg penetration seals are satisfactory and that upgrading tNse seals is not required.
Combustible loading in the CSR is primarily cable insulation, most of which is equivalent to the fire resistance criteria of IEEE Standard 383. Most of the cable, including all of the non-fire-retardant cable, has been coated with a fire-retardant material.
Alternative safe shutdown systems that are independent of both the Control Room and the CSR have been installed.
The alternative safe shutdown systems, complete with detailed emergency operating procedures, are available for use in the event of a fire in either or both rooms, and exceed the requirements of Appendix R, both in redundancy and in plant functions provided.
Although the Control Room and the CSR are listed as separate Appendix R fire areas, a major fire in either area would disable the safe shutdown components in the other, regardless of the fire Darrier between them.
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!, The Control Room floor /CSR ceiling is a twelve-inch-thick slab of concrete.
Other than some penetration seals and a small amount of uncoated structural steel, the concrete floor is capable of achievino a three-hour rating.
Structural steel under the Control Room floor /CSR ceiling has been covered with a fire-resistant coating at all accessible points; the remaining uncoated steel has been found acceptable in an SER.
Although some of the penetrations are not thred-hour rated, they all provide a level of protection commensurate with the barrier's Appendix R requirements. Therefore, the Control Room floor /CSR ceiling provides adequate fire protection to the Control Room and the CSR.
Oue to congestion under the CSR ceiling, upgrading the penetration seals would recuire disruption of many circuits, some of which are safety-related, with extensive impact on time and resources and a potential negative impact on safety.
About 250 holes (typically 6-inch diameter) form the penetrations of interest.
All of the openings were initially sealed with a combination of fire retardant foam material, mineral fiber and cementitious ornut. This was found acceptable by the staff. The upper surface of all o# the penetration seals has been visually examined oy the licensee and found to be in satisfactory condition.
The bottom surface of approximately 10% of these penetration seals cannot be inspected due to cable congestion. However, the remaining seals have been insoected and determined to be satisfactory.
In addition, the licensee performed a full discharge test of the total flooding Halon suppression system in the CSR following installation.
No difficulty was experienced in reaching and maintaining the desiqr.
concentrations of Halon in the room.
This would not have been the case if significant leaks erteo in the enclosing barriers, thus, providino indirect evidence that the perietration seals are intact.
The staff agrees with the licensee's position, that considering the combination of conditions that exist in the plant, it is not necessary in the interests of fire protection to upgrade the uninspectable penetration seals in the CSR ceiling /CR floor to 3-hour fire resistance rating.
3.0 CONCLUSION
On the basis of the above Evaluation, we conclude that the existing penetration seals in the Cable Spreading Room ceiling / Cont.'o; Room floor assembly are satisfactory and do not need to be upgraded to a full 3-hour fire resistance ratino. We also reaffirm the 1981 exemption from the requirements of Appendix R to 10 CFR 50 for automatic suppression in the Control Room even though the exerotion was originally granted, in part, on the basis of 3-hour fire n ating of the CSR ceiling /CR floor assembly.
Principal Contributor:
D. Notley
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Mr. Ralph G. Bird Boston Edison Company Pilgrim Nuclear Power Station cc:
Mr. K. P. Roberts Nuclear Operations Boston Edison Cnmoany Pilgrim Nuclear Power Station ATTN:
Mr. Ralph G. Bird Boston Edison Company Senior Vice President - Nuclear RFD dl, Rocky Hill Road 800 Boylston Street Plymouth, Massachusetts 02360 Roston, Massachusetts 02199 Resident Inspector's Office Mr. Richard N. Swanson, Manager U. S. Nuclear Regulatory Commission Nuclear Engineering Geoartment Post Office Onx 867 Boston Edison Company Plymouth, Massachusetts 02360 25 Braintree Hill Park Reaintree, Massachusetts 02184 Chairman, Board of Selectmen 11 Lincoln Street Ms. Elaine D. Robinson Plymouth, Massachusetts 02360 Nuclear Infornation Manaoer Pilgrim Nuclear Power Station Office of the Commissioner RF0 dl, Rocky Hill Road Massachusetts Department of Plymouth, Massachusetts 02360 Environmental Quality Engineering One Winter Streat Roston, Massachusetts 02108 Office of the Attorney General 1 Ashburton Place 20th Floor Boston, Massachusetts 02108 Charles V. Berry Secretary of Public Safety Mr. Robert M. Hallisey, Director Executive Office of Public Safety Radiation Control Program One Ashburton Place Massachusetts Department of Roston, Massachusetts 02108 Public Health 150 Tremont Street, 2nd Floor Boston, Massachusetts 02111 Regional Administrator, Region i U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 Mr. James D. Keyes Regulatory Affairs and Programs Group Leader 90ston Edison Company 25 Braintree Hill Park Braintree, Massachusetts 02184 d
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