ML20205E816
| ML20205E816 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 10/21/1988 |
| From: | Partlow J NRC OFFICE OF SPECIAL PROJECTS |
| To: | TENNESSEE VALLEY AUTHORITY |
| Shared Package | |
| ML20205E822 | List: |
| References | |
| NUDOCS 8810270480 | |
| Download: ML20205E816 (9) | |
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l UNITED STATES OF AMERICA NUCLEAR REGL'LATORY COMMISSION
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In the Matter of
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TENNESSEE VALLEY AUTHORITY Docket Nns. 50-259, 50-260
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and 50-796 (Browns Ferry Nuclear Phnt,
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Units 1, 2 and 3)
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EXEMPTION 1.
The Tennessee Valley Authority (TVA or the licensee) is the holder of Operating License No. OPR-33 which authorizes operation of Browns Ferry Nuclear Plant (BFNP) Unit 1, Operating License No. DPR-52 which authorizes I
operation of Unit 2. and Operating License No. OPR-68 which authorizes operatinn of Un't 3.
The licenses provide, among other things, that the plant is subject to all rules, regulations, and Orders of the Comission now or hereafter in effect.
The plant is comprised of three boiling water reactors (PWRs) at the licensee's site located near Decatur, Alabama.
II.
On November 10, 1980, the Comission published a revised Section 50.48 and a new Appendix R to 10 CFR Part 50 regarding fire protection features of nuclear power plants (45 FR 76602). The revised Section 50.48 and Appendix R t'ecame effective on February 17. 1981.
Section III of Appendix R contains 15 subsections, lettered A through 0, each of which specified requirements for SS10270480 881021 PDR ADOCK 05000259 F
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2 a particular aspect of the fire protection features at a nuclear power plant, Two of these subsections, III.L and III.G. are the subject of the licensee's exemption request.
Subsection III.L.1 of Appendix R requires that the alternative shutdown capability be able to maintain the reactor coolant system process variables within those predicted for a loss of normal ac power, and Section III.L.2.b of Appendix R reouires that the reactor ecolant makeup function maintain the coolant level above the top of the core for BWRs.
Subsection III.G.2 of Appendix R requires that one train of cables and equipment necessary to achieve and maintain safe shutdown be maintained free of fire damage by one of the following means:
a.
Separation of cables and equipment and associated non-safety
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circuits of redundant trains by a fire barrier with a 3-hour rating.
Structural steel forming a part of or supporting such fire
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barrier shall be protected to provide fire resistance equivalent to 1
that required of the barrier, b.
Separation of cables and equipment and associated non-safety circuits of redundant trains by a horizontal distance of more than 20 feet free of intervening combustible 2 or fire hazards.
In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area, c.
Enclosure of cable and equipment and associated non-safety circuits of one redundant train in a fire barrier with a 1-hour rating.
In addition, fire detectors and an automatic fire suppression system shall be installed in the fire area.
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. Subsection III.G.3 of Appendix R requires that where Subsection III.G.2 cannot be met, alternative or dedicated shutdown capability shall be provided. For areas where alternative and dedicated shutdown is provided, fire detection and a fixed suppression system shall also be installed in the areas, room, or zone under consideration.
III.
By letter dated January 31, 1986, the licensee requested exemptions from specific requirements of Appendix R.
By letters dated November 21, 1986 May 26, 1937 September 14, 1987 and April A. 1988, the licansee provided additional information to support and to modify certain exemption requests identified in the January 31, 1986 submittal. A description of the exemptions requested and the acceptability of these exemptions are addressed below. The Commission staff's detailed Safety Evaluation is concurrently being issued.
Exemptinn Requested The licensee requested an exemption from the requirements of Appendix R to 10 CFR Part 50.Section III.L. Items III.L.1.b and III.L.?.b.
These items require that the reactor coolant make-up function associated with the alternative / dedicated shutdown system previded for a specific fire area be capable of maintaining the reactor coolant level above the top of the core for BWRs (III.L.2.b) and, thus, assure that the systen has the capability to r'aintain the reactor coolant inventory (III.L.1.b).
Contrary to this, temporary uncovering of the core may be experienced as provided in the licensee's submittal.
The licensee has determined and the staff concurs that the duration of core uncovery is not long enough to result in damage to the core. Also, maximum suppression pool temperatures attained still allow for opera, tion of
. Subsection !!!.G.3 of Appendix R recuires that where Subsection !!I.G.2 cannot be met, alternative or dedicated shutdown capability shall be provided. For areas where alternative and dedicated shutdown is provided, fire detection and a fixed suppression system shall also be installed in the I
areas, room, or zone under consideration.
By letter dated January 31, 1986, the licensee requested exemptions from specific requirements of Appendix R.
By letters dated November 21, 1986, May 26, 1987, September 14, 1987 and April A, 1988, the licensee provided additional information to support and to modify certain exemption requests identified in the January 31, 1986 submittal.
A description of the exemptions requested and the acceptability of these exemption. are addressed below.
The Commission staff's detailed Safety Evaluation is concurrently being issued.
l Exemptinn Requested l
The licensee requested an exemption from the requirements of Appendix R to 10 CFR Part 50 Section III.L. Items III.L.1.b and III.L.?.b. These items require that the reactor coolant make-up function associated with the alternative / dedicated shutdown system provided for a specific fire area be capable of maintaining the reactor coolant level above the top of the core for BWRs (!!!.L.2.b) and, thus, assure that the systen has the capability to maintain the reactor coolant inventory (!!!.L.1.b). Contrary to this, temporary uncovering of the core may be experienced as provided in the licensee's submittal.
The licensee has determined and the staff concurs that the duration of core uncovery is not long enough to result in damage to the core.
- Also, maximum suppression pool temperatures attained still allow for, opera. tion of
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4 the residual heat removal (RHR) system (i.e., net positive suction head (NPSH)
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requirementscanbemet).
1 The special circumstances of 10 CFR 50.12 apply since application of the i
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regulation in the particular circumstances is not necessary w achiave the underlying purpose of the rule. Although momentary uncovering cf the core may
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occur, licensee has performed detailed heat transfer analysis confiming lack of fuel clad damage in the core.
Subsection !!!.L. requires that where alternative or dedicated safe shutdown capability is provided for a specific 1
fire area that it be able to effect safe shutdown of the plant. The perfomance j
goals specified in Subsection !!!.L.2.b for the shutdown functions state shat the reactor coolant level be maintained above the top of the fuel for BWPs.
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The underlying purpose of this performance goal is to prevent fuel clad damage l
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and thus core damage. The licensee has demonstrated, notwithstanding a t
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nomentary coolant level drop below the top of the active core, that there will l
I be no damage to fuel cladding and, therefore, to the core.
Therefore, the l
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underlying purpose of the rule is satisfied because the licensee has demonstrated that the plant can be safely shut down without fuel cladding i
i darrage.
Exemption Requested An exemption was requested from the specific requirements of
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I Section !!!.G.3 to the extent that a fixed fire suppression system is not j
provided in an area (Fire Area 16) for which an alternative shutdown I
capability is provided.
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The licensee has provided an independent alternative shutdown capability I
for the main control rooms in Fire Area 16.
The control roons have autor.atic I
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. fire detection systems installed and they are continuously manned.
There are fire extinguishers and a hose station available for manual fire fighting. A postulatt.d fire in this area is not expected to threaten other safe shutdown areas adjacent to it because of the existence of fire rated barriers and other fire protection features.
Therefore, a fixed fire suppression system installation would not significantly upgrade the level of fire protection.
The special circumstances of 10 CFR 50.12 apply since application of the regulatien in the particular circumstances is not necessary to achieve the underlying purpose of the rule.
The underlying purpose of Subsection I!!.G.3 is ach kved by having the control room continously manned and fire mitigation equiprrent loc ted in the rooms. Thus, the underlying purpose of the rule l
l would be satisfied without installing a fixed fire suppression system in the control room.
Exerotion Requested An exemption was requested from the specific requirements of Subsection !!!.G.2.b to the extent that areas centaining redundant trains of j
RHR pumps and heat exchangers are not provided with an automatic fire l
suppression system (RPR Pumps - Fire Zeres 1-1, 1-2, 2-1, 2-2, 3-1, and 3-?-
l Heat Exchanger Rooms - Fire Zones 1-3, 2-4, and 3-3).
Fire Zones 1-1, 1-2, 1-3, 2-1, 2-2, 2-4, 3-1, 3-2, and 3-3 are in the RHR pump and heat exchanger rooms.
The fire loads in these :ones is low to negligible.
The lieersee has provided fire detection systens and has installed water curtains and draft stops. These features provide reasonable assurance that a fire would remain small, be easily extincuished by the fire brigade, and not threaten adjacent plant areas or redundant PHR
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i equipment / cables which have a separation of more than 70 feet. Therefore, the l
1 installation of an automatic fire suppression system is not required.
i The special circumstarces of 10 CFR 50.12 apply since application of the j
regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule.
As discussed above, the underlying purpose of I
Subsection III.G.? is achieved by spatial separation in excess of the
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requirements (70 feet versus 20 feet), existing and proposed fire protection l
features and a low combustible load.
Therefore, the underlying purpose of the
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rule would be satisfied without installation of automatic fire suppression
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systen in the above Fire Zones.
l Exemption Requested I
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An exemption was requested from the specific reauirements of
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Subsection III.G.2.b to the extent that it requires no intervening J
combustibles within a 20-foot separation space provided t'etween redundant safe j
shutdown system components.
This exemption covers each Reactor Building for i
all three units.
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With respect to each peactor Building, it is found that the fire severity t
based on the existing combustible loading is substantially less than the fire i
rating of the existing fire barriers. Certain vertical penetrations such as l
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equipment hatches are adequately protected by either heavy metal covers or a
water curtains. Area wide fire detection and sprinkler systems coupled with j
local supplemental sprinkler coverage and nanual extinguishers and hose i
l stations are provided in the Reactor Buildings.
Should a fire occur in a j
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Reacter Building, it is expected to develop slowly, be detected early, and
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be extinguished by either an automatic fire suppression system or by the i
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7 fire brigade. Therefore, it is concluded that the fire protection features in the reactor buildings provide a level of fire protection equivalent to the requirements of Subsection III.G.2.b.
The special circurastances of 10 CFR 50.12 apply since application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule. As discussed above, the undcriying purpose of i
Subsection III.G.2 is achieved by means of sprinkler system coverage, area wide detection and spatial separation of cables.
Therefore, the underlying purpose of the rule would be satisfied without removal of intervening l
l combustibles.
l Exemption Requested Exemptions were reouested from the specific requirements of Subser. tion III.G.3 of Appendix R to the extent that fixed fire detection and suppression systems were not provided in areas for which alternative shutdown capability has been provided (Control Building - Fire Area 16).
l The principal concern is that fire in this fire area could spread to a critical area and cause a loss of normal shutdown capability.
The Control Building has f$re rated barriers that exceed the expected fire severity based i
on the fire load within or near the affected areas. There are fire extinguishers and hose stations available for ranual fire fighting.
Therefore, there is reasonable assurance that a fire in this area could be l
readily extinguished by the fire brigade. The licensee has not provided a fire detection systee for all location
- in this fire area, however, there is reasonab e assurance that a fire it, this fire area would not propagate beyond the specific area origin.
Should a fire occur and damage redundant normal safe J
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shutdown components within the aforementioned fire area, the alternative j
safe shutdown would be available to maintain safe shutdown.
The special circumstances of 10 CFR 50.12 apply sf nce application of the I
regulation in the particular circumstances is not neces:ary to achieve the l
underlying purpose of the rule. With th.$ orovided fire ptotection features l
discussed above and a limited quantity of embustible materials, the staff i
concludes that the underlying purpose of Section III.G.3 is a-hieve.i. Thus, i
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area-wide fixed suppression and detection system in Conttol Puilding h. not j
i necessary to provide reasonable assurance that a fire would be detected and j
suppressed and post-fire capability maintained free of fire damage.
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IV.
s Accordingly, the Comission has determined, pursuant to 10 CFR 50.12(a),
j that (1) these exemptions described in Section III are authorized by law and l
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will not present an undue risk to the public health and safety and are consistent with common defense and security, and (2) special circumstances are present 'er the exemptions in that application of the regulation in these particular circumstances is not necessary to achieve the un(eelying purposes i
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of Appenoix R to 10 CFR Part 50 Therefore, the Cemission Nreby grants the exemptions from the requirements of Sections !!I.L and III.G af Appendix R to I
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10 CFR Part 50 as follows:
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! l Core Uncovery to the extent that alternative shutdown capability is 1.
not able to maintain reactor coolant inventory above the core in a BWR as required by Section !!!.L of Appendix R.
The Pain Control Room to the extent that a fixed suppression system c
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is not provided throughout the area as required by Section I!!.G of i
I Appendix R.
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RHR Pump Rooms and Heat Exchanger Rooms to the extent that an automatic fire suppression system is not provided as required by i
Section !!!.G of Appendix R.
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The Reactor Buildings to the extent that Section III.G of Appendix R l
requires that there be no intervening combustibles within a 20 fcot j
separation space between redundant safe shutdown system components.
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The Control Building to the extent that Section !!I.G.3 requires installation of fire detection and fixed fire suppression in the fire i
areas for which an alternative shutdown capability has been provided.
i Pursuant to 10 CfR 51.32, the Commission has determined that the granting i
I of these exemptions will have no significant inpact of the environment 1
i October 19, 1938 (53 FR 40979)
A copy of the licensee's requests for exemptions dated January 31, 1986
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h and subsequent documents as well as the Safety Eveluation dated j
l 1988, related to this action is available for public inspection at the I
Comission's Public Document Poom, 2120 L Street, N.V., Washington, D.C. and
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t at the local public document room located at Athens Public Library, South Street, j
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Athens. Alabama 35611. A copy may be obtained upen written request addressed l
to the U.S. Nuclear Regulatory Comission, Washington, D.C.
20555 Attention:
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l Director, Office of Special Projects.
This Exemption is effective upon issuance.
1 Dated at Rockville, Maryland this 21st day of October 1988.
d FOR THE NUCLEAR REGULATORY COMMISSION i
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j Ja nes G. Partlow, Director Office of Special Projects j
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