NRC Generic Letter 1983-033: NRC Positions on Certain Requirements of Appendix R to 10 CFR 50ML031080522 |
Person / Time |
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Site: |
Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000514, 05000000, 05000496, 05000497, 05000515, Zimmer, Fort Saint Vrain, Washington Public Power Supply System, Shoreham, Satsop, Trojan, Clinch River, Skagit, Marble Hill, Black Fox |
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Issue date: |
10/19/1983 |
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From: |
Eisenhut D Office of Nuclear Reactor Regulation |
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To: |
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References |
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GL-83-033, NUDOCS 8310200362 |
Download: ML031080522 (7) |
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Similar Documents at Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000514, 05000000, 05000496, 05000497, 05000515, Zimmer, Fort Saint Vrain, Washington Public Power Supply System, Shoreham, Satsop, Trojan, Clinch River, Skagit, Marble Hill, Black Fox |
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Category:NRC Generic Letter
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Letter 1994-002: Long-Item Solutions and Upgrade of Interim Operating Recommendations for Thermal Hydraulic Instabilities in Boiling Water Reactors NRC Generic Letter 1994-011994-05-31031 May 1994 NRC Generic Letter 1994-001: Removal of Accelerated Testing and Special Reporting Requirements for Emergency Diesel Generators NRC Generic Letter 1993-081993-12-29029 December 1993 NRC Generic Letter 1993-008: Relocation of Technical Specification Tables of Instrument Response Time Limits NRC Generic Letter 1993-071993-12-28028 December 1993 NRC Generic Letter 1993-007: Modification of Technical Specification Administrative Control Requirements for Emergency & Security Plans NRC Generic Letter 1993-061993-10-25025 October 1993 NRC Generic Letter 1993-006: Research Results on Generic Safety Issue 106, Piping and the Use of Highly Combustible Gases in Vital Areas. NRC Generic Letter 1993-051993-09-27027 September 1993 NRC Generic Letter 1993-005: Line-Item Technical Specifications Improvements to Reduce Surveillance Requirements for Testing During Power Operation NRC Generic Letter 1993-041993-06-21021 June 1993 NRC Generic Letter 1993-004: Rod Control System Failure and Withdrawal of Rod Control Cluster Assemblies, 10 CFR 50.54(f) NRC Generic Letter 1993-021993-03-23023 March 1993 NRC Generic Letter 1993-002: Public Workshop on Commercial Grade Procurement and Dedication NRC Generic Letter 1993-011993-03-0303 March 1993 NRC Generic Letter 1993-001: Emergency Response Data System Test Program 2023-08-03 The following query condition could not be considered due to this wiki's restrictions on query size or depth: <code> [[:Beaver Valley]] OR [[:Millstone]] OR [[:Hatch]] OR [[:Monticello]] OR [[:Calvert Cliffs]] OR [[:Dresden]] OR [[:Davis Besse]] OR [[:Peach Bottom]] OR [[:Browns Ferry]] OR [[:Salem]] OR [[:Oconee]] OR [[:Mcguire]] OR [[:Nine Mile Point]] OR [[:Palisades]] OR [[:Palo Verde]] OR [[:Perry]] OR [[:Indian Point]] OR [[:Fermi]] OR [[:Kewaunee]] OR [[:Catawba]] OR [[:Harris]] OR [[:Wolf Creek]] OR [[:Saint Lucie]] OR [[:Point Beach]] OR [[:Oyster Creek]] OR [[:Watts Bar]] OR [[:Hope Creek]] OR [[:Grand Gulf]] OR [[:Cooper]] OR [[:Sequoyah]] OR [[:Byron]] OR [[:Pilgrim]] OR [[:Arkansas Nuclear]] OR [[:Three Mile Island]] OR [[:Braidwood]] OR [[:Susquehanna]] OR [[:Summer]] OR [[:Prairie Island]] OR [[:Columbia]] OR [[:Seabrook]] OR [[:Brunswick]] OR [[:Surry]] OR [[:Limerick]] OR [[:North Anna]] OR [[:Turkey Point]] OR [[:River Bend]] OR [[:Vermont Yankee]] OR [[:Crystal River]] OR [[:Haddam Neck]] OR [[:Ginna]] OR [[:Diablo Canyon]] OR [[:Callaway]] OR [[:Vogtle]] OR [[:Waterford]] OR [[:Duane Arnold]] OR [[:Farley]] OR [[:Robinson]] OR [[:South Texas]] OR [[:San Onofre]] OR [[:Cook]] OR [[:Comanche Peak]] OR [[:Yankee Rowe]] OR [[:Maine Yankee]] OR [[:Quad Cities]] OR [[:Humboldt Bay]] OR [[:La Crosse]] OR [[:Big Rock Point]] OR [[:Rancho Seco]] OR [[:Zion]] OR [[:Midland]] OR [[:Bellefonte]] OR [[:Fort Calhoun]] OR [[:FitzPatrick]] OR [[:McGuire]] OR [[:LaSalle]] OR [[:05000514]] OR [[:05000000]] OR [[:05000496]] OR [[:05000497]] OR [[:05000515]] OR [[:Zimmer]] OR [[:Fort Saint Vrain]] OR [[:Washington Public Power Supply System]] OR [[:Shoreham]] OR [[:Satsop]] OR [[:Trojan]] OR [[:Clinch River]] OR [[:Skagit]] OR [[:Marble Hill]] OR [[:Black Fox]] </code>.
[Table view]The following query condition could not be considered due to this wiki's restrictions on query size or depth: <code> [[:Beaver Valley]] OR [[:Millstone]] OR [[:Hatch]] OR [[:Monticello]] OR [[:Calvert Cliffs]] OR [[:Dresden]] OR [[:Davis Besse]] OR [[:Peach Bottom]] OR [[:Browns Ferry]] OR [[:Salem]] OR [[:Oconee]] OR [[:Mcguire]] OR [[:Nine Mile Point]] OR [[:Palisades]] OR [[:Palo Verde]] OR [[:Perry]] OR [[:Indian Point]] OR [[:Fermi]] OR [[:Kewaunee]] OR [[:Catawba]] OR [[:Harris]] OR [[:Wolf Creek]] OR [[:Saint Lucie]] OR [[:Point Beach]] OR [[:Oyster Creek]] OR [[:Watts Bar]] OR [[:Hope Creek]] OR [[:Grand Gulf]] OR [[:Cooper]] OR [[:Sequoyah]] OR [[:Byron]] OR [[:Pilgrim]] OR [[:Arkansas Nuclear]] OR [[:Three Mile Island]] OR [[:Braidwood]] OR [[:Susquehanna]] OR [[:Summer]] OR [[:Prairie Island]] OR [[:Columbia]] OR [[:Seabrook]] OR [[:Brunswick]] OR [[:Surry]] OR [[:Limerick]] OR [[:North Anna]] OR [[:Turkey Point]] OR [[:River Bend]] OR [[:Vermont Yankee]] OR [[:Crystal River]] OR [[:Haddam Neck]] OR [[:Ginna]] OR [[:Diablo Canyon]] OR [[:Callaway]] OR [[:Vogtle]] OR [[:Waterford]] OR [[:Duane Arnold]] OR [[:Farley]] OR [[:Robinson]] OR [[:South Texas]] OR [[:San Onofre]] OR [[:Cook]] OR [[:Comanche Peak]] OR [[:Yankee Rowe]] OR [[:Maine Yankee]] OR [[:Quad Cities]] OR [[:Humboldt Bay]] OR [[:La Crosse]] OR [[:Big Rock Point]] OR [[:Rancho Seco]] OR [[:Zion]] OR [[:Midland]] OR [[:Bellefonte]] OR [[:Fort Calhoun]] OR [[:FitzPatrick]] OR [[:McGuire]] OR [[:LaSalle]] OR [[:05000514]] OR [[:05000000]] OR [[:05000496]] OR [[:05000497]] OR [[:05000515]] OR [[:Zimmer]] OR [[:Fort Saint Vrain]] OR [[:Washington Public Power Supply System]] OR [[:Shoreham]] OR [[:Satsop]] OR [[:Trojan]] OR [[:Clinch River]] OR [[:Skagit]] OR [[:Marble Hill]] OR [[:Black Fox]] </code>. |
-4
TO ALL LICENSEES AND APPLICANTS OF NUCLEAR POWER REACTORS
Gentlemen:
SUBJECT: NRC POSITIONS ON CERTAIN REQUIREMENTS OF APPENDIX R
TO 10 CFR 50 (GENERIC LETTER 83-33)
During our evaluations of exemption requests, we determined that some licensees were interpreting certain requirements of Appendix R in a manner that was not consistent with the position that the staff was using. Where..
any such differences were discovered, we informed these licensees in the NRC Safety Evaluation Report supporting the granting or denial of an -
exemption. More recently, we have completed inspections for conformance to Appendix R at four plants, the licensees for which had indicated that all modifications for conformance had been completed or other modifications approved by exemptions had been completed. In these inspections, the NRC
inspection team also identified what the staff considers to be non- conformance with requirements of Appendix R, for which ex&eptions had not been requested or justified.
Therefore, we are transmitting the enclosure to all licensees and applicants for information and use as appropriate. The NRC inspection teams that will be conducting the inspections for conformance to Appendix R at each plant will be using these positions as their criteria for conformance for these particular issues. No written response to this letter is required.
Sincerely, Darrell G. Ei n Director Division of Licensing Office of Nuclear Reactor Regulation Enclosure:
As stated
8310200362
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dir NRC Staff Positions on Certain Requirements of Appendix R to 10 CFR 50
Introduction During our reviews of Appendix R exemption requests and our review of appli- cations for operating licenses, it has become apparent that certain require- ments of Appendix R to 10 CFR 50 and the corresponding guidelines in SRP 9.5-1 were not being interpreted correctly by some licensees. On several occasions members of the staff met with representatives of the Nuclear Utility Fire Protection Group (NUFPG), other industry representa- tives, and individual licensees to disucss clarification of certain requirements. The staff agreed to send the staff positions on these issues to all licensees.
1. Detection And Automatic Suppression Staff Position: Subsections III.G.2.b, III.G.2.c, and III.G.2.e require that fire detectors and an automatic fire suppression system be installed "in" any fire area. To satisfy this requirement, the fire detectors and automatic suppression system need to be installed "throughout" the fire area.
Some licensees have not interpreted "in" the fire area to require full detection and suppression "throughout" the fire area. This interpre- tation makes the requirement ambiguous.
In some fire areas, however, the installation of a fire detection and a fire suppression system throughout the fire area may not significantly increase the level of fire safety afforded by only partial coverage; or the installa- tion of a fire suppression system throughout the area may be detrimental to overall plant safety. Such areas must be evaluated under the exemption process, along with a fire hazards analysis that shows the installation of fire detection and/or suppression systems in only select locations within the fire area will provide an equivalent level of protection.
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2. Fire Areas Staff Position: Section III.G of Appendix R sets forth the requirement for fire protection for safe shutdown capability on the basis of fire areas.
A fire area is defined as that portion of a building or plant that is separated from other areas by boundary fire barriers (walls, floors and ceilings with any openings or penetrations protected with seals or closures having a fire resistance rating equal to that required of the barrier).
Open stairwells and hatchways in ceilings and floors are not fire area boundaries.
For boundary fire barriers, using walls, floors, ceilings, dampers, doors, etc. existing prior to Appendix R, the rating required of a boundary fire barrier is based on the guidance in Appendix A to BTP ASB 9.5-1, i.e.,
the rating of the barrier or boundary must exceed with margin the fire loading in the area and need not necessarily be a 3-hour rated boundary unless the fire loading warrants such a boundary. For modifications which involve the installation of new boundary fire barriers pursuant to Section III.G.2.a, the fire rating of such boundaries must be three hours, or an exemption must be justified and requested.
The evaluations by some licensees made prior to Appendix R were based on fire zones which do not meet the strict definition of fire areas clarified above. In some cases, the separation of redundant trains under consideration within the "fire zone boundaries" and the separation between fire zones does not comply with the separation, i.e., barrier or distance, requirements of Appendix R. Such configureations need to be evaluated under the exemption process.
The fire protection requirements are intended to provide reasonable assurance that at least one safe shutdown division is free of fire damage after a postulated fire in any fire area. The definition of "fire areas,"
noted above, is predicated on sound fire protection engineering principles
-3- as they apply to limiting the fire and fire suppressant damage to redundant shutdown equipment and cables. Fire areas defined by non-physical bounda- ries, such as "logical divisions" or "equipment groupings", may not necessarily restrict fire and smoke spread, and do not necessarily provide reasonable assurance that the limits of fire or fire suppressant damage to shutdown systems have been defined.
In many plant areas, however, the erection of physical barriers between redundant shutdown systems is precluded by the location of cable trays, HYAC ducts and other plant features. In such situations, the staff has accepted, in concept, the use of an automatic fire suppression system which discharges a "water curtain" across the boundary areas separating the redundant systems. The design of such "water curtains" has not been codified, i.e., the National Fire Protection Association Standards do not address the use of fire suppression systems for such applications. How- ever, the staff is currently working with several applicants and licensees to define design requirements which will satisfy mutual concerns. The staff's present position is that such systems should feature close-spaced, open-head sprinklers with water discharge initiated by tripping a deluge valve activated by cross-zoned smoke detectors. Where smoke propagation does not represent a hazard to redundant shutdown systems, a close-space, close-head sprinkler system may be deemed acceptable. Where such "water curtains" are used, the operation of such systems should not endanger safety systems on either side of the "water curtains."
3. Structural Steel Related To Fire Barriers Staff Position: Appendix R requires that structural steel forming a part of, or supporting a fire barrier separating redundant trains shall be pro- tected so as to have a fire rating equivalent to the fire resistance required of the barrier.
K A
-4- The protection of structural steel is required because steel loses strength when subjected to temperatures that may be attained in a fire.
1100 degrees Fahrenheit is normally considered to be the critical tempera- ture. At this temperature the yield stress in steel has decreased to about
60 percent of the value at room temperature. This *isapproximately the level normally used as the design working stress. Because steel has a high thermal conductivity, and heat is transferred away from a localized heat source rather quickly, a relatively long period of time is required to reach the critical temperature. However, an exposure fire that dis- tributes heat over a greater area may reduce this time considerably.
Structural steel need only be rated to the level of the barrier of which it is a part, based on the combustible loading in the area. If protection is required to achieve such a rating, then the steel would have to be protected. In cases where the structural steel is not protected and has a lower fire rating than the required rating of the fire barrier, an exemption must be requested and justified by a fire hazards analysis which shows the temperature the steel will reach during fire, and the ability of the steel to carry the required loads at that temperature.
4. Fixed Suppression System Staff Position: A fixed fire suppression system shall have discharge heads and the distribution piping for such heads installed. Hose stations do not satisfy this requirements.
The majority of areas for which a fixed fire suppression system is required contain large concentrations of cables and, therefore, have high fire loadings. In addition, access for fire fighting may be hampered by congestion and smoke. A fixed fire suppression system should be capable of controlling a fire in such areas even under limited access conditions.
5. Intervening Combustibles Staff Position: Section III.G.2.b requires the "separation . . . with no intervening combustibles . . ." To meet this requirement, plastic jackets and insulation of grouped electrical cables, including those which are coated, should be considered as intervening combustibles.
Numerous comprehensive flammability tests conducted by the Electric Power Research Institute (EPRI NP-1200, EPRI EL-1263), Factory Mutual (Contract RP-1165-1), and Sandia National Laboratories (NUREG/CR-2431, among others) have shown that burning plastic cable insulation represents a significant fire hazard. These tests were conducted on both IEEE-383 qualified and unqualified cable. While the qualified cable exhibited a tendency to ignite and propagate flame less rapidly, combustion of grouped cables continued at significant levels. In particular, grouped vertical cables which are not protected by a fire propagation retardant, such as metal tray covers or fire retardant coatings, can result in rapidly developing fires with high heat release rates.
6. Transient Fire Hazards Staff Position: When addressing transient combustibles in exemption requests, the fire hazards analysis should consider the conservative bounding value for a transient fire hazard that could reasonably be expected over the life of the plant.
Over the past few several years, several attempts have been made by the NRC and industry to develop criteria for establishing "design basis transient combustibles." These have been suggested:
' e, ( !
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1. The maximum amounts permitted by the plant's administrative controls or some multiple of that amount.
2. Selected amounts (e.g., 1 pint, 1 quart, or 1-20 gallons) of a combustible liquid (e.g., acetone, heptane, lube oil, or solvents).
However, none of these criteria have stood up to critical evaluation as to why they are bounding conditions in all possible circumstances. During the life of the plant, transient combustible materials may be located in, or pass through safety related areas. These hazards arise from activities associated with operation, maintenance, repairs or modifications. They may arrive deliberately under approved work permits or inadvertently as a temporary expedient. Usually, a fire involving such materials would not overpower the fire protection features provided in accordance with Section III.G and, therefore, are only of concern when exemptions or deviations are requested.
In reviewing "transient combustibles" when evaluating exemption requests, the staff considers, among other things: (1) the physical attributes of the area that will tend to limit the amounts of transient combustibles, e.g., restricted access due to the environment within the area and loca- tion of the area or physical access limitations; (2) whether the fire area is required by the plant Technical Specifications to be manned continuously;
(3) the physical attributes of the fire area and configuration of the systems of concern which apply to their capability to limit fire and fire suppressant damage; and (4) the safety significance of the systems of concern.
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