ML20082Q474
| ML20082Q474 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 09/04/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20082Q473 | List: |
| References | |
| NUDOCS 9109120189 | |
| Download: ML20082Q474 (3) | |
Text
{{#Wiki_filter:_ _. n, l . ju nto -!\\(w E UNITED STATES n -{c - f [i. NUCLEAR REGULATORY COMMISSION WASHINoToN. D C. 20565 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.175 TO FACILITY OPERATING LICENSE NO. DPR-49 IOWA ELECTRIC LIGHT AND POWER COMPANY CENTRAL IDWA POWLR C00PERAllVL { TORN BELT POWER COOPERATIVE DUANE ARN0L9 ENERGY CENTER DOCKET N0. 50-331 i
1.0 INTRODUCTION
By letter dated February 22, 1991, the Iowa Electric Light and Power Company (the licensee) requested chsnges in the Technical Specification surveillance for the fire pumps installed at the Duane Arnold Energy Center (DAEC). The staff's evaluation of the requested changes is based on review of supporting justification furnished by the licensee in its February 22, 1991 letter :nd its letter response dated June 14, 1991, to questions posed verbally to the licensee in March and again on May 29, 1991. 2.0 EVALVATION Two_ fire pumps, one electric-motor driven and the other diesel-engine driven, supply all fire protection water at the DAEC. Either one of the pumps is designed to provide 100% of the maximum expected fire flow requirements for the plant. The DAEC Technical Specification 4.13.B.1.e requires that each fire pu.np develop a flow of at least 3100 gallons per minute (g[m) with a discharge pressure of 112-pounds-per-square-inch gage (psig). During Inspection No. 90-015, the NRC Region 111 fire protection inspector noted that both fire pumps failed those flow requirements during the annual test on Saptember 13, 1990. This failure was cit e in the inspection report as a Severity Level IV violation. The licensee's initial response was to deny the violation. Its position was that: Automatic sprinkler system No. 4 was the limiting factor in originally establishing the large flow and pressure requirements for the fire pump. Water flow for the entire area protected by sprinkler system No. 4 had improperly been assumed in the original calculations. The ifcensee intended tc rec 1culate system water flow demands using a smaller and more realistic area so as to snow that the existing fire pumps were adequate. 91091k!C189 910904 PDR ADOCK 0S000331 L
L =., y{ 2 Sprinkler system No. 4 protects the Turbine Building Heater Bay. While it contains safety-related components, the licensee believed (and intended-to verify) that no safe shutdown components were located in the protected area and loss by fire of any of the components in this area would have no effect on safe shutdown. The results of that recalculation indicated that actual fire pump requirements were approximately 3100 gpm at 140 psig rather than the 112 psig requirement of Technical Specification 4.13.B.1.e. The licensee then proposed using its service water pumps as the backup to the fire pumps. After considerable di.ccussion, che licensee and staff agreed that: since the service water pumps cannot meet the identified water flow requirements, they cannot be considered an acceptable backup system; if the licensee can demonstrate that both fire pumps together can deliver the identified water flow requirements, they will be considered an acceptable backup system; and the licensee will perform a detailed study of the entire fire protection water supply system to determine realistic maximum flow demands, and modifications which might improve flow characteristics. In addition, the licensee was to implement a continuous fire watch throughout areas with safe shutdown equipment that are protected with automatic sprinklers, including the area protected by sprinkler system No. 4, except for high radiation areas where remote surveillance cameras would be installed. These fire watches were to be maintained until the licensee was able to place acceptable backup fire pump (s) in service. On May 29, 1991, the licensee called to say that the snaft seal on the electric motor driven fire pump was leaking during the regular monthly surveillance test. It was concerned tha+ if it attempted to repair the fire pump shaft seal packing and something should go wrong, it would not be able to complete the repair within the required 4 hours. It would then have to initiate a plant trip and shut down in accordance with its Technical Specification requirements of Section 3.13.B.3.d. It d'scussed with the staff the possibility of expediting this review so as to relieve DAEC from continuing to consider both fire pumps running as being necessary to qualify as a backup system. A favorable conclusion is necessary as a result of this. review in order to find the existing pumps acceptable. Most of the underground fire main is 6-inch-diameter pipe. However, the two fire pumps were connected to the main by three short sections of 4-inch pipe. ^ During the reevaluation mentioned abovt, the licensee determined that replacing those three sections _of 4-inch pipe with 6-inch would substantially reduce friction losses and, therefore, the discharge pressure requirements for l l l
... M1 J 1 M.1 ,'..[ -3 the fire pumps. The licensee has made those piping changes. With all 6-inch piping installed, the licensu has determined the minimum required flow for each pump to be at least 3115 gpm with a pump discharge pressure of at least 96 psig. The staff reviewed the material submitted by the licensee with its letter of February 22, 1991, and in March asked the licensee by telecon for clarification of its modifications to the Fire Protection System. The staff also asked for clarification of its nntation "that the existing values for Sprinkler System #4 did not accurately reflect the current piping configuration." During a telecon on May 30, 1991, the same questions were again asked of the licensee. Its letter of June 14, 1991, responds to those questions. The staff has reviewed the licensee's June 14, 1991 letter and finds the responses to its questions acceptable. Based on the above evaluation, the staff concludes that the licensee's proposed Technical Specification surveillance requirer.ients for acceptable minimum flow of DAEC fire pumps of at leest 3115 gpm with a discharge pressure of at least 96 psig are acceptable. 3.0 S_ TATE CONSULTATION In accordance with the Commission's regulations, the Iowa State official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
S This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement. The staff has 6etermined that the amencment insolves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a prop'; sed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (56 FR 33958). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no enviro. iental impact statement or environmental assessment need be prepo;ed in connection with the issuance of the amendment.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed chove, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public. Principal Contributor: D. P. Notley Date: September 4, 1991 _}}