ML18033B382
| ML18033B382 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/31/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18033B375 | List: |
| References | |
| NUDOCS 9006210245 | |
| Download: ML18033B382 (6) | |
Text
UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION EMPLOYEE CONCERN 23100 FIRE PROTECTION DESIGN BROWNS FERRY UNITS 1
2 AND 3 TENNESSEE VALLEY AUTHORITY DOCKET NOS. 50-259 260 296 1.0 STATEMENT OF EMPLOYEE CONCERN The employee concern 23100, Fire Protection Design was made up of the following elements.
231.1 231.2 231.3 231,4 231.5 231.6 Undersized distribution headers Electrical panels not protected from sprinklers Sprinkler head spray pattern interference Lack of fire dampers in additional diesel generator building Adequacy of battery room ventilation system design Fire protection gA designationI 2.0
SUMMARY
AND EVALUATION t
Of the six elements under employee concern
- 23100, TVA determined that only three were applicable to Brown's Ferry Units 1, 2 and 3.
These elements are:
231.1 231.5 231.6 Undersized Distribution headers Adequacy of battery room ventilation system design Fire protection gA designation The other three elements represented concerns that identified specific plant components at Watts Bar or Sequoyah, and therefore, were not considered generic by TVA.
The staff agrees with this assessment.
Element 231.1 is composed of the following issues:
a) Welding small pipes to large pipes could result in flow restrictions b) Review of such piping by an independent authority is recommended (all plants) c) At Sequoyah and Watts Bar, high pressure fire protection system piping, sizing and confiouration are not in accordance with National Fire Pro-tection Association (NFPA)
In regard to (a) and (b) which mav be applicable to Brown's Ferry, TVA has concluded that an independent review of NFPA code deviations would answer the concern.
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TVA has completed the review and issued the report on NFPA code devfatfons.
It was submitted to NRC in August 1988.
The staff evaluated the report and found some deviations to be allowable for restart and others to require a more definitive completion or modification schedule.
The staff position on NFPA
-code deviations at BFN was transmitted to TVA and TVA responded by letter to staff concerns on February 3, 1989, R. L..Grfdley to NRC.
Element 231.5 Adequacy of battery room ventilation is composed of the following issues:
a) The design of the battery room heating and ventilating system is inadequate.
b} Hydrogen could accumulate, especially ff battery room fans failed.
c) Electric heaters could ignite hydrogen The TVA investigation of battery room HVAC design showed that the battery rooms are envfronmenta'lly controlled to maintain an average annual temperature of about 77'F.
The ventilation requirements result in a minimum of 2 air changes per hour fn winter which results in a maximum hydrogen concentration of 2 percent.
The redundant fans fn the battery rooms are supplied from the Class 1E power bus.
Flow indicators or alarms are provided locally or in the main control room.
There are no electric heaters fn the plant battery rooms.
The diesel generator battery ventilation hoods do not have redundant fans and flow alarms or indicators; however, there are no dampers fn the exhaust ducts, thus allowing natural ventilation to keep the hydrogen concentration in the hoods below 2 percent should the fans fail.
Standard practice for conduct of operations requires that local control panels, meters, indicators, pressures, and motors be checked every shift (8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />).
This includes ventilation and charging systems.
Although there are electrfc heaters in the UG room ceilings the limitations on hydrogen concentration wfthfn the hoods effectively preclude ignition.
The staff believes that TVA has adequately addressed this concern.
Element 231.6 is composed of the following issues:
a) Requirements for limited gA (quality assurance) for fire protection systems were contradicted by engineering drawings.
b) At Bellefonte, such requirements were improperly implied This concern was raised at Bellefonte Nuclear Plant fn regard to TVA's general construction specification G-73, "Inspection, Testing and Documentation Requirements for Ffro Protection Systems and Features."
The concern was that TVA engineering did not establish the gualfty Assurance (gA) requirements for fire protection features consistent with the requirements of specification G-73.
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General construction specification G-73 establishes minimum inspection, testing and documentation requirements for fire protection systems and features for TVA nuclear power plants to assure compliance with quality assurance requirements set forth by the NRC.
Fire protection systems are generally installed under a "limited gA program" and fall under the requirements of G-73 for construction documentation.
The "limited gA program" provides a full documentation program for the construction and installation of fire protection features.
but is of reduced scope from the traditional gA requirements of 10 CFR 50, Appendix B.
This program was developed to meet the NRC fire protection guidelines.
Fire protection systems which interact with nuclear safety systems such as those in which seismic supports are needed, must confrom to the gA requirements of 10 CFR 50, Appendix B.
The staff concludes that TVA's quality assurance program for fire protection systems and components is in accordance with US NRC SRP 9.5.1 (NUREG 0800) in regard to the scope and application of general construction specification G-73.
3.0 CONCLUSION
The staff concludes that of the six elements under employee concern 23100 "Fire Protection Design" only three are applicable to Browns Ferry Nuclear Plant.
These three are:
231.l Undersized Distribution Header 231.6 Adequacy of battery room ventilation system design 231.6 Fire Protection gA designation The staff concludes that concern 23l.l "Undersized Distribution Headers" has been adequately addressed by the TVA study and report on NFPA code deviations.
The staff concludes that concern 231.5 "Adequacy of battery room ventilation system design" has been adequately addressed from a technical standpoint.
The staff concludes that concern 231.6 "Fire Protection gA Designation" will not be a concern at Browns Ferry Nuclear Plant because the application of gA in regard to Fire Protection Systems at BFN is in accordance with SRP 9.5.1 requirements.
I 1l