ML20216K022
| ML20216K022 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 09/12/1997 |
| From: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9709180177 | |
| Download: ML20216K022 (4) | |
Text
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.s CurnIs 11. CuesE Italtimore Gas and Electric Company Vice President Cahert Cliffs Nuclear Power Plant Nuclear EnerFy 1650 Calsert Cliffs Parkway Lusby, Maryland 20657 410 495-4455 September 12,1997 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk SUILIECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Emergency Diesel Generator Upgrade Project - Temocrarv t.
nption Request
REFERENCES:
(a)
Letter from Mr. R. E. Denton (BGE) to NRC Document Control Desk, dated December 17,1993, Emergency Diesel Generator Upgrade Project
- Temporary Exemption Request (b)
Letter from Mr. R. E. Denton (BGE) to NRC Document Control Desk, dated Augurt 4,1994, Emergency Diesel Generator Upgrade Project -
Temporary Exemption Request The No. IB Emergency Diesel Generator (EDG) will be modified during the upcoming Unit I refueling outage (spring 1998) to increase its rated electrical capacity. This modification will provide additional margin for the electrical loading of the associated 4.16 kV safety-related bus. Following the physical modification work, qualification testing will be performed in accordance with the reviewed and approved testing program. In order to perform this modification, a temporary exemption from the requirements of
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General Design Criteria (GDC) 2 (1967 draft) is needed. This is similar to the temporary exemption o
requested in References (a) and (b). The major differences are that there are now four EDGs, the identification numbers of all the EDGs have changed, and two missile doors will be opened instead of one.
Pursuant to 10 CFR 50.12(a), Baltimore Gas and Electric Company requests a temporary exemption from the requirements of draft GDC-2, or equivalent relief. Temporary relief from draft GDC-2 is requested as it relates to the desiga of a system essential to the mitigation of an accident to withstand the effects of natural phenomena. This relief will permit the temporary removal of the steel missile doors that provide missile protection for No. IB and 2A EDGs and support systems common to Fairbanks Morse No. IB, 2A, and 2B EDGs. We have identified the need to remove the missile doors approximately four times during the refueling outage for a period of about 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> each removal.
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Docum:nt Control Desk
' September 12,1997 Page 2 Baltimore Gas and Electric Company believes that the standards of 10 CFR 50.12 are satided in this Special circumstances are present, as described in 10 CFR 50.12(a)(2)(iv) and (v), to warrant case.
granting the temporary exemption. This temporary exemption will indirectly result in benefits to the public from the increased capacity of one of the EDGs. The temporary exemption is requested for a specific period; at all other times the facility will be in conformance with the requirements of dran GDC-2, Baltimore Gas and Electric Company is committed to minimizing the time the missile doors are removed.
BACKGROUND Dran GDC-2 states, "Those systems and components of reactor facilities which are essential to the prevention of accidents which could affect the public health and safety or to mitigation of their consequences shall be designed, fabricated, and erected to performance standards that will enable the facility to withstand, without loss of the capability to protect the public, the additional forces that might ie imposed by natural phenomena such as earthquakes, tornados, flooding conditions, winds, ice, and other local site effects. The design bases so established shall reflect: (a) appropriate consideration of the most severe of these natural phenomena that have been recorded for the site and the surrounding area and (b)an appropriate margin for withstanding forces greater than those recorded to reflect uncertainties about the historical data and their suitability as a basis for design." As stated in our Final Sarcty Analysis Report submittal (1971), the plant design r.nd construction proceeded based upon the intent of the draft GDC.
Our EDGs are systems that prevent and mitigate the consequences of an accident. The Calvert Cliffs site has four EDGs (I A, IB,2A, and 2B). Each unit has two EDGs assigned to it. Three of the EDGs (IB, 2A, and 28) are in rooms in the Auxiliary Building and share common operating systems. Le fourth is in a separate building and does not share operating systems with the other three. The Auxiliary Building is a Class I structure, one of whose functions is to protect the EDGs and their support systems from tornado-borne missiles. Each of the Auxiliary Building EDG rooms was designed with a large opening on the western side to allow for movement of the diesel engine into or out of the room. These openings are covered by steel doors that provide missile protection equivalent to that provided by the concrete walls. Each of these rooms contains a diesel generator, its local controls, and support systems. The rooms that contain No.1B and 2A EDGs, contain a starting air header, which is common to No. IB,2A, and 2B EDGs. In addition, the No.1B and 2A EDG share a common concrete block wall, which is not designed to withstand missile impingement.
During the period of the temporary exemption, Unit I will be defueled for the spring 1998 refueling outage. Unit 2 will be operating in Mode 1. Unit I does not require an operable EDG while defueled-No. IB EDG will be inoperable for the duration of the upgrade. Unit 2 requires two operable EDGs in Mode 1 (Technical Specification 3.8.1.1). Both the No. 2A and 2B EDG will be operable for Unit 2.
When the missile door is removed from the No. IB EDG room, the missile protection is also defeated for the No. 2A EDG because of the shared concrete block wall. When the missile door for the No. 2A EDG room is removed, missile protection is also defeated for No. IB EDG (out-of-service) because of the shared concrete block wall. fn addition, when either door is removed, missile protection is defeated for all three EDGs because of the common starting air system present in both rooms.
I
Document Control Desk
' September 12,1997 Page 3 Performance of the upgrade on No. !B EDO will entail removal and replacement of several large components on the engine. Unlike the other EDO rooms, the No. IB EDG room configuration is such that large components cannot be moved past the front of the engine. The front of the engine is the part nearest the missile door. Compor ents being removed will be taken to the rear of the No.1B engine, through a connecting door to the No. 2A EDG room, and then out the No. 2A missile door opening. The move-in of some of the new components will follow the reverse of this process. Most of the components will be moved into the No. IB EDO room through the No. 2A EDG room, llowever, the heat exchanger tube bundles are expected to be moved in and out through the No. IB missile door. The following are examples of components that are of a size and weight that make rigging in and out of the labyrinth personnel door of the EDO rooms impossible, thereby requiring missile door removal:
Blower 42" x 40" x 48" 2400 lbs Turbos (2) 28" dia. x 34" deep 1800 lbs Air inlet Pipe 28" x 40" x 25" 430 lbs Intercoolers (2) 15" x 15" x 59" 520 lbs lleat Exchanger Tube Bundles 14" dia. x 95" long i154 lbs Based on the current work scope, we expect there to be a total of four removals between the two doors during the upgrade work. Each removal is expected to be less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in duration. Only one door will be removed at a time. When a missile door is removed, it will remain connected to the crane used to remove it, This will permit rapid reinstallation, if necessary. We are requesting a temporary exemption to GDC-2 (draft) only for those periods when a missile door is removed from the opening to either EDG room.
IHE REOUIREMENTS OF 10 CFR 50.12 ARE MET The standards set forth in 10 CFR 50.12 provide that specific exemptions will be granted which:
are authorized by law; are consistent with the common defense and security; will not present an undue risk to the public health and safety; and are accompanied by special circumstances.
Baltimore Gas and Electric Company believes that the activities to be conducted under the temporary
- exemption are clearly authorized by law and are consistent with the common defense and security. The remaining standards for the temporary exemption are also satisfied, as described below.
No Undue Risk The temporary exemption will not present an undue risk to the public health and safety. Baltimore Gas and Electric Company will take compensatory actions to reduce the risk of missile damage to the affected EDG and common EDG support systems for the period of the temporary exemption. Only one missile door will be removed at a time. The removal of each missile door will be for such a short period of time that the missile door will remain corpected to the crane used to remove it. While a missile door is removed, operat;ons personnel will remain cognizant of approaching weather systemr Personnel responsible for supervising the installation of the modification will be notified if a tornado or hurricane
a Document Control Desk
' September 12,1997 Page 4 watch is issued for the plant site or sustained winds at the plant site are predicted to be above 50 miles / hour. If such conditions occur, a concerted effort will be made to reinstall the missile door before the arrival of the storm. This effort will be limited only by the need to ensure the safety of the individuals performing the work.
Special Circumstatters This request involves special circumstances as set forth in 10 CFR 50.12 (a)(2)(iv) and (v). The temporary exemption will indirectly result in benefits to the public from the increased capacity of No.1B EDO. In addition, the temporary exemption would provide only temporary relief from the applicable regulation. The temporary exemption is requested for a speciGed, limited period of time -about four missile shield removals for approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> each - during the Spring 1998 refueling outage.
Therefoie, the temporary exemption would provide only temporary relief for the period necessary to move equipment in and out of the room.
Without the requested temporary exemption, it will not be possible to perform the upgrade work on the EDG without requiring the operating unit (Unit 2) to be snut down. We are committed to making good faith efforts to provide missile protection for the EDG support systems during the temporary exemption period. As noted abcve, we will be prepared to reinstall the open missile door whenever there is a threat of a tornado at the Cahut Cliffs site. We are also limiting the amount of time cach missile door is removed.
SCIIEDULE The first removal of the missile doors is currently scheduled to take place during the outage that will start about April 3,1998. Therefore, we request that this temporary exemption be grvted prior to that date.
CONCLUSIOli Baltimore Gas and Electric Company believes the standards of 10 CFR 50.12 are satisfied, including the existence of special circumstances as required by 50.12(a)(2)(iv) and (v). This temporary exemption is necessary to permit a desirable upgrade to the EDG without an unnecessary unit shutdown.
Should you have questions regarding this matter, oe will be pleased to discuss them with you.
Very truly yours, f
f 'z !/ f b
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cc:
R. S. Flekhman, Esquire II. J. Miller, NRC J. E. Silberg, Esquire Resident inspector, NRC Director, Project Directorate I-1, NRC R.1. McLean, DNR A. W. Dromerick, NRC J.11. Walter, PSC
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