ML19318B199
| ML19318B199 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 06/24/1980 |
| From: | Sylvia B VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Harold Denton, Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0660, RTR-NUREG-660 NUDOCS 8006250120 | |
| Download: ML19318B199 (10) | |
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VinoisrA ELEC*rIMC AND Pow e n Co>uwxy nrenxox u,vinorm noce>n June 24, 1980 9
Mr. Harold R. Denton, Director Serial No. 550 Office of Nuclear Reactor Regulation N0/FHT:ms ATTN:
Mr. B. Joe Youngblood, Chief Docket No. 50-339 Licensing Branch No. 1 License No. NPF-7 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Dear Mr. Denton:
NORTH ANNA POWER STATION UNIT NO. 2 AUXILLARY FEEDWATER SYSTEM INFORMATION
)
As required by the North Anna Unit 2 Safety Evaluation Report section 10-2, item II.K.3. and by the TMI Action Plan, NUREG-0660, item II.E.1.1, we are forwarding the attached Comparison of the North Anna Auxiliary Feedwater System with the Standard Review Plan.
Additionally, in response to inquires from your staff we are providing the following supplemental information.
1.
The North Anna Unit 2 auxiliary feedwater system is essentially identical to the North Anna Unit I auxiliary feedwater system and therefore the reliability study performed by your staff for North Anna Ur.it 1 is directly applicable to North Anna Unit 2.
2.
Our letter of May 19, 1930, Serial No. 406, provided the status of the implementation of the redundant indication of Emergency Conden-sate Storage Tank (ECST), vater level. The short term requirement for redundant indication of ECST water level has been fulfilled.
This redundant level transmitter will provide the operator with both ECST level indic trion and a low level alarm in the main control room. The alarm will be set to alert the <>perator of ECST iow level at least twenty (20) minutes before tha ECST could be emptied by the largest auxiliary feedwater (AFW) pump.
Materials required to upgrade this redundant indication to sa f e ty-grade are presently on order.
We expect delivery during the fourth quarter of 1980, and will schedule installation of the safety grade equipment for the first outage of sufficient duration following receipt of material.
THIS DOCUMENT CONTAINS POOR QUALITY PAGES 8000sgo I go
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Ysk is A EttcTu:c Axo Powra Comsy T Mr.
Harold R.
Denton 2
If you have any questions, or require additional information, please contact this office.
Very truly yours, B. R. Sylvia Manager-Nuclear Operations and Maintenance Attachment cc: Mr. James P. O'Reilly t
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Attachment page 1 of 8 COMPARISON OF THE NORTH ANNA AUXILIARY FEEDWATER SYSTEM WITH THE STANDARD REVIEW PLA'I Listed below are the Standard Review Plan Acceptance. Criteria Items and Vepco's corresponding responses.
- 1. through 7.
The Standard Review Plan requires compliance with Gene-ral Desigts Criteria-2, 4, 5, 19, 44, 45, and 46 for the anvillary.feedwater system.
Response
The North Anna Unit 1 & 2 auxiliary feedwater systera, being a safety-related systen, falls under the requirement s of FSAR Section 3.1.
In this section, it states:
- Structures, systems and components importan t to safety are designed to ceet the intent of the General Design. Criteria (GDC).
The GDC and explanations of how the structures, syste=s, and components meet the intent of the GDC are found in Sections 3.1.1 through 3.1.55."
Because the North Anna FD.R was developed in compliance with the General Design Criteria, ' the auxiliary feedwater system is in agreement with the Stsndard Review Plan.
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-page 2 of 8 8.
The Standard 1 view Plan requires compliance with Regulatory-Guide 1.26, as related to the quality group classification of system coruponents.
Regulatory Guide 1.26 desc r ibes a quality classification sys te:a fac safety-related-components.
The system consists of methods for assigning components to - quality groups, and the spec ific standards applicable to
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each group.
Response
The North Anna FSAR discusses quality classification in Section 3.2.2 and the impracticality of classifying the components into the groups _ listed in Regulatory Guide 1.26.
There it states:
"The group classifications tabulated in the ' Standard Format and Content of Safety Analysis Reports for Nuclear Fower Reactors' issued February 1971, and in Sa fety Guide No. 26 published March, 1972, incorporate, in most cases, later editions of codes than those in effect when the majority of safety related equipment was designed.
Socte of the equipment
' group' as defined in Safe ty Guide which would fall under a No. 26 was designed for dif ferent codes or different editions of the same code.
For example, for dif ferent components which would be in the same group, one may be designed to ASME III-1971, and one to ASME VIIII-1953.
Therefore, pressure-containing components of safety related systens do not fall under the group classifications listed above."
i Since the issue of the FSAR, the Vepco Nuclear Power Station Quality Assurance y2nual has been revised to include a quality classification systens in accordance with Regulato g Guide 1.26.
Therefore, the design of the North Anna Units 1 & 2 auxiliary feedwater systen teets the intent of Regulatory Guide 1.26.
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The Standard' Review Plan requires compliance with Regulatory Guide 1.29, as related to the seismic design classification of system components.
Regulatory Guide 1.29 requires that-the auxiliary feedwa te r ystem be designated as Seismic Category I and the pertinent quality assurance re-quirements of. Appendix B to 10CFR50 be applied to the system.-
Response
Table'3.2.1-1 of the North Anna-FSAR lists systems designed to seismic Category I.
Lis ted in the table are those pertinent components of the auxiliary feedwater system.
Vepco's Nuclear Power Station Quality Assurance Manual applies to all Category I systems and was developed in accordance with Appendix B to 10CFR50.
There fo re, the North Anna auxi-11ary feedwater system meets the requirements of Regulatory Guide 1.29.
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Pagm 4 of 8 10.
The Standard Review Plan requires compliance with Regulatory Guida 1.62, related to design provisions made for manual initiation of each pro-as
- tec t ive ac t ion.
Regulatory Guide 1.62 describes means for initiation-of protective actica including manual initiation that performs all actions performed by auto-
- natic - initiation with switches located in the control room.
The amount of equipment common to both manual and automatic initiation should be kept to a minimum and initiation should depend.on the operation of a
- ninimum of equipment. Once initiated, the system should go to completion as required in Section 4.16 of IEEE Standard 279-1971.
Response
Section 10.4.3 of the North Anna FSAR discusses initiation of the auxi-liary feedwater system.
Only one operator action, per train, is necessary t o. place the auxiliary feedwater system into ope ration.
Manual start switches are available on the cain control board for both notor driven and turbine driven auxiliary feedwater pumps.
All valves in the systen are normally aligned for operation and annunciate when not fully aligned to assure a flow path when pumps are started.
After completion, return to operation requires subsequent deliberate operator action as specified in IEEE Standard 279-1971.
Therefore, the North Anna Units 1 & 2 auxiliary feedwater system is in compliance with Regulatory Guide 1.62.
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Page 5 of 8 11.
The Standard Review Plan requires compliance with Regulatory Guide 1.102, as' related to the protection of structures, systems, and components important to safety from the effects of flooding.
Descriptions of types of flood protection acceptable to the NRC staf f and riethods of protec ting nuclear power plants from the effects of Probable Maximus Precipitation (PMP) falling directly on the site are provided in Regulatory Guide 1.102.
Response
The flood protection analysis performed for North Anna Units 1 and 2 is presented in FSAR Section 2.5 and Appendix J.
The auxiliary feedwater system and structure are in compliance with Regulatory Guide 1.102.
How-ever, reanalysis of site flooding vill be performed at a later date to reflect the final site grading plan, including the effec ts of the drainage area west of Units 1 and 2.
The flood protection data presented irt the FSAR for Units 1 and 2 does not include the effects of the drainage area
- west-of Units 1 and 2, either as a construction site or as a completed site for Units 3 and 4.
Site in tensive local precipitation will have no flooding ef fect on North Anna Units 1 and 2 due to Units 3 and 4 construction site grading.
In-suf fic ient rainfall will be collected in the construction excavation area vest of Unit 2, which is at elevation 230' (elevation 204' in the con-tainment area), to raise the water level above the point where it would be of concern (elevation 254') due to the extremely small drainage area of the site itself.
However, when the P2 occurs ove r the Lake Anna drainage bssin, the construc tion excavation could be flooded to lake level through the Units 3 and 4 circulating water intake and discharge tunnels.
Tne PMP level for the excavation area would be at approximately elevation 264'.. A sand bag dike has been built to elevation 258'-6" in Units 3 and 4 discharge tunnels.
We are reifewing -construction flood protection for North Anna Units 3 and 4 to protect North Anna Units 1 and 2 fr= -S m at approximately elevation 264'.
At the 17 line of Unit 2 Turbine Building, a reinforced concrete flood wall has been built to elevation 257'.
The auxiliary feedwater pump switchgear. -inich is located in the Service Building at elevation 254',
is ::::S r p m ectad from flooding, via che Turbine Sn ild ing. by a flood eill r - a n tton 237' at cae Se rvia 3ttiilia; entrance.
Tec h n ie.t1 3 pec i-fica:ica.;.7.6.1 requires plant shutdown withia 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> should the warer level at the main reservoir spillway rise above elevation 256'.
Vepco's letter to the SRC dated May 23, 1930 pro rides additional inforna-tion on floodplain management for North Anna.
From the information above, it is concluded that the North Anna Units 1
& 2 Auxiliary Feedwate r System is in compliance with Pcgulatory Guide j
1.102.
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The Standard Pseview Plan requires compliance with Regulatory Guide 1.117, as. related 'to the protection of structures, systems, and components important to safety from the effects of tornado missles.
Methods acceptable to the NRC staff for identifying those s t ructures, systems, and components that should be protected from the effects of the
' Design Basis Tornado,(specified in Regulatory Guide 1.76) are provided in Regulatory Guide 1.117.
Auxiliary Feedwater Systems are among those systems identified as being protected from Design Basis Tornado.
Reponse:
The table below shows the design basis tornado characteristics specified by Regulatory Guide 1.76 and North Anna FSAR Section 3.3.2.
DESIGN BASIS TORNADO CHARACTERISTICS Radius of Translatio..al Maximum Maximum Rotational Speed (2ph)
Rotational Pressure Rate of Wind Speed Speed Speed Drop Pressure Source (oph)
(aph)
Minimum
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(feet)
(psi)
Drop (psi /sec'r R.G.
1.25 360 290 70 5
150 3.0 2.0 FSAR 360 300 60 500 3.0 3.0 As illustrated above, the North Anna Units 1 & 2 auxiliary feedwater systec neets the intent of Regulato y' Guide 1.117.
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The Standard Review Plan requires compliance with Branch Technical Posi-l' tions ASB 3-1 and MEB 3-1, as related to breaks in high and moderate energy piping systems outside containment.
- The Branch Technical Position defines a high energy fluid system as:
" Fluid systems that, during normal plant conditions,.tre either in operation or maintained pressurized under conditions where either or both of the following are met:
maximum operating temperature exceeds 200*F, o_r a.
b.
maximum operating pressure exceeds 275 psig."
Response
The North Anna FSAR Appendix C defines high energy line breaks in thc'e systems in which both the maximum operating pressure exceeded 275 psig and the maximum operating temperatures equalled or exceeded 200 degrees F.
Since the auxiliary feedwater system did not meet the 200 degree F requirecent, high energy pipe breaks were not considered.
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Pagn 8 of 8 14.
The Staedard Review Plan requires compliance with Branch Techni.:al Posi-tion ASB 10-1, as related to' auxiliary feedwater pump drive and power supply diversity.
The auxiliary feedwater system is in compliance with Branch Technical Position ASB 10-1, as related to pump drive and power supply diversity.
This is based on the response to NRC question 10.19, statements made by the NRC staff in the Safety Evaluation Report for tiorth Anna Power Station Units 1 and 2, dated June 4,1976 and by a recent review of the system.
Section 10.5, of the SER states:
" Based on our review, we conclude that the auxiliary feedwater system design is in conforcance with our Brm:
Technical post-tion APCSB 10-1 regarding diversity of powe. sources, system ficxibility and redundancy including the combination single ac tive failure and high energy line break and is, therefore, acceptable."
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