ML17319B616

DC Cook Nuclear Plant Units 1 & 2,Seismic Qualification of Auxiliary Feedwater Sys, Technical Evaluation Rept

ML17319B616
Person / Time
Site:	Cook
Issue date:	09/03/1982
From:	LAWRENCE LIVERMORE NATIONAL LABORATORY
To:	NRC
Shared Package
ML17319B615	List: ML17319B616
References
GL-81-14, NUDOCS 8211010412
Download: ML17319B616 (11)

Text

TECHNICAL EVALUATION REPORT Donald C. Cook Nuclear Plant Units 1 and 2 SEISMIC QUALIFICATION OF AUXILIARYFEEDWATER SYSTEM

1. INTRODUCTION Since the accident at, Three Mile Island, considerable attention has been focused on the capability of nuclear power plants to reliably remove decay heat. The NRC has recently undertaken Multiplant Action Plan C-14 "Seismic Qualification of AFW Systems" [Ref. 1], which is the subject of'his evaluation.

To implement the first phase of Action Plan C-14, the. NRC issued G neric Letter No. 81-14 "Seismic Qualification of AFW Systems" [Ref. 23, dated February 10, 1981, to all operatino PWR licensees. This letter requested each licensee (1) to conduct a walk-down of nonseismically qualified portions of the AFW system and identify deficiencies amenable to simple actions to improve seismic resistance, and (2) to provide design information reoarding the seismic capability of the AFW system to facilitate NRC backfit decisions.

The licensee of D.C. Cook Nuclear Plant Units 1 6 2 responded with a.

letter dated August 28, 1981 [Ref. 3). T¹ licensee's response was found not to be complete and a Request for Additional Information (RAI) was issued by the NRC, dated April 5, 1982 [Ref. 4]. The licensee provided a supplemental response in a letter dated Dune 15, l982 [Ref. 5j.

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This report provides a technical evaluation of the information provided in the licensee's responses to. the Generic Letter, and includes a regarding the need for additional analysis and/or uporading 'ecommendation modifications of this plant.'s AFW system.

2. EVALUATION Information provided in licensee's responses included:

o Specificaton of the overall seismic capability of the AFW system.

o Identification of AFW system components that are currently non-seismically qualified for SSE.

o D'scussion of levels of seismic capability of non-seismically qualified components.

D scription of the AFW system boundary.

Status of ccmpliance with seismic related NRC Bulletins and Information Notices.

Results of partial walk-down of the non-seismically qualified piping, and schedule for the ongoing field verification of the remainino non-seismically piping.

Additionall diaorams of the AFW system.

Additionally, description of methodologies and acceptance criteria for seismically qualified components.

We have reviewed the licensee's responses, and a point-by-point evaluation of licensee's responses against Generic Letter's requirements is provided belo~.

(1) S ism'c Ca abilit of AFÃ S stem Except for those items identified in the following, the AFM system has been designed, constructed and maintained to withstand an SSE utilizing'methods and acceptance criteria consistent with those applicable to other safety-related systems in the plant. Presently, those items identified by the licensee as not, being fully qualified seismically are evaluated below:

o Pumps/Motors - None, o ~pi in - (a) The condensate'stotageCank associate piping was desioned to seismic Class EI criteria. The condensate storaoe tank itself is seismic Class II and was designed to the OBE level.

However, *a seismic Class I secondary water. source, i.e., the essential service water system, exists at the plant. The'refore, we judge that this piping is not essential to the safety related V

function of the AFW system. (b) The main feedwater piping upstream from the check valve to the motor operated valve is classified as seismic Class III, but was designed to the USAS B 31.1, 1967 edition and to withstand the OBE. Additionally, this segment of piping is part of licensee's ASME BhPV Code, Section XI, Cod Class 2 Surveilance Program. Since the portion of the main feedwater piping discussed in (b) above is required to accomplish the AFH system function, we conclude that, the AFW system piping possesses a seismic capability of the OBE level although the AFH system piping itself is seismically qualified to the SSE level.

Valves/Actuators None

Pow r Suppl Licensee indicated that th Y switcho ~

cabinets TllA to D, the 600V switchgear cabinets llA to D, and the reactor trip and bypass breakez cabinets were found to be inadequately installed against overturning during the SSE.

Ho~ever, the permanent modification of the anchorage has b en completed by Auoust 28, 1981, and.we therefore conclude that the will withstand 1

power supplies now possess a seismic capability that an SSE.

Water. Source(s) - The primary water source, i.e., t¹ condensate storage tank, is seismic Class II and was designed to the OBE level. The secondary water source is the seismic Class I essential service water system. The procedure to s~itch the AFW pump suction to the essential service'water system exists and is in place at the plant,. Details of the procedure were described in licensee's.

letter to NRC dated Parch 28, 1980, No. AEP:NRC:0307A, and the procedure was accepted by NRC via S. Varga's letter of 0:tober 6, 1980 to the licensee. We conclude that the water sources possess an SS level. of seismic capacity.

Initiation/Control S stems None Structures - On the suction side, close to the condensate storage tank, the first valve'and about three feet of piping are seismic Class I but do not have a seismic Class I enclosure. Tho enclosure provided is a fabricated sheet metal enclosure and the licensee did r

not. discuss its seismic capacity. We judge that the structures possess an OBE level- of overall seismic capacity. However, it is not cleaz to us whether the portion of the piping protected by the f

non-seismically qualified enclosure is part of the primary water source and path. If this is the case, the failure of the enclosure should not, affect the safety related function of the A.-"W system.

Baseo on our eva tion d scribed above, those'r as of the AFH.system judoed not .to possess an SSE level of seismic capabili y are identified below".

Pumps/Motors None

~Pi ill OBE Yalves/Actuators None

~S1 None Source(s)

'ater None Initiation/Control S stems None Structures None+

+The level becomes OBF if the seoment of piping protected by the non-seismically qualified. enclosure structure is not part of the primary water source and path.

In summary, our evaluation indicated that the majority of the AFÃ system at D. C. Cook Nuclear Plant Units 1 and 2 presently possess a level of seismic capability that can withstand 'an SSE with the exception of a portion of the main feedwater piping connected to the AFW system and, possibly, one piping enclosure structure as discussed above.

The primary water source and supply path is not se'sr;.ically qualified

.and, therefore, switchover to the seism'cally qualified secondary water source and supply path, i.e., the essential service water syst m, is requied. The switchover procedure is available at the plant and was ac"epted by the NRC..

The seismic qualification information for any alternate decay heat removal system was not, provided-in the 3.icensee-s responses. This infm~ation was requested by the G neric Letter if substantial lack of seismic qualification is. indicated for the AFW system. Based on the submitted.

information from licensee's responses, we find that thAFW system is not fully capable of performing the requirqd safety-related function following the occurrence of an SSE. Therefore, we conclude that the licensee is required to either provide the information on seismic qualification of any alternate decay heat removal system or- reanalyze/upgrade the existing AFW system to withstand the SSE.

Regarding the AFW system boundary, the licensee stateo that the boundary of the AFH system as currently evaluated coincice with the boundary definition specified in GL 81-14. The licensee also stated that all work applicable to the AFW system for IE Bulletins 79-02 and 79-07 is completed; work applicable

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to the AFW system for IE Bulletin 79-14 and 80-11 is presently being completed; and IE Infornation Notice 80-21 is currently under review. The licensee also indicated that IE Bulletin 79-04 is not applicable to the AFW system re-evaluation because IE Bulletin 79-04 was issued in reference to incorrect weights for Velan swing check valves and there are no Velan valves in the AFW system for D. C. Cook Plant. We conclude that the AFW system is included within the scope of the applicable seismic related NRC Bulleti'ns and Information Notices.

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(2) Walk-Down of Non-Seismicall Qualified Portions of'FW. System

~ I A walk-down of the non-seismically qualified portion of the AFW system is required. The licensee indicated that walk-down has been conducted for the non-seismically qualified piping connected to the condensate storage tanks and no deficiencies were identified. The licensee also indicated that efforts are underway to verify in the field the portion of the seismic Class III main feedwater piping upstream from the check valve to the motor-operated valve.

As part of this effort, the licensee identified one valve control cabinet missing the anchorage shown on the design drawinos. This deficiency was immediately repaired and reported to the NRC, Region III. The licensee will submit the results of the fieldwalk once it is completed, currently scheduled to be during the next refueling outage.

(3) Additional Information The licensee provided a feedwa'ter diagram and main steam diagram which illustrate the boundary of the AFW system. Additionally, licensee's responses provided a description of the methodologies, loading combinations and acceptance criteria that were used in the design of the seismically qualified

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portion of the AFW system

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3. CONCLUSIONS The information contained in licensee s respon'ses to Gl 81-14 is complete. The licensee has conducted a partial walk-down for the non-seismically qualified pipino and is currently performing another field r

walk-down oi the remaining non-seismically qualified pipino scheduled to be completed during the next refueling outage.

Based on the submitted information, we judge that the AFW system at D. C. Cook Nuclear Plant, with the exception of a portion of the main feedwater pip'na connected to the AFH system'and'one enclosure structure, presently provides a reasonable assurance to perform its required safety functions followino an SSE. In conclusion, we recommend that, the NRC consider r quirino the licensee to reanalyze and/or upgrade the AFH system to assure an overall seismic capability of the SSE level.

REFERENCES

l. D. G, Eisenhut, U. S. Nuclear Regulatory Commission, memorandum to H. R.

Dent. on, "Multiplant Action Plan C-14: Seismic Qualification of Auxiliary I

Feedwater Systems," February 20, 1981.

2. U. S. Nuclear Reoulatory Commission, Generic letter No. 81-14 to all operating pressurized water reactor licensees, "Seismic Qualification of Auxiliary Feedwater Systems," February 10, 1981.

3. R. S. Hunter, Indiana h Michigan Electric Co., letter to H. R. Denton of U. S. Nuclear Reoulatory Commission, Auoust 28, 1981.

A. S. A. Varga, U. S. Nuclear Reoulatory Commission, letter to R.S. Hunter of Indiana h Michigan Electric Co., "Request for Additional Information on Seismic Qualification of the Auxiliary Feedwater System, Donald C.

Cook Nuclear Plant Units 1 and 2," April 5, 1982.

5. R. S. Hunter, Indiana h Michigan Electric Co., letter to H. R. Denton of U. S. Nuclear Regulatory Commission,Dune 15, 1982.

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