ML19257D123
| ML19257D123 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck, Millstone File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 01/24/1980 |
| From: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8002010344 | |
| Download: ML19257D123 (10) | |
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January 24, 1980 Docket Nos. 50-213 50-245 Director of Nuclear Reactor Regulation Attn:
Mr. D. L. Ziemann, Chief Operating Reactors Branch #2 U. S. Nuclear Regulatory Commission Washington, D. C.
20555
References:
(1)
D. L. Ziemann letter to W. G. Counsil dated October 3,1978.
(2)
D. L. Ziemann letter to W. G. Counsil dated September 26, 1978.
Gentlemen:
Haddam Neck Plant Millstone Nuclear Power Station, Unit No. 1 Fire Protection Modifications In References (1) and (2), the NRC Staff documented its requirements regarding fire protection-related modifications for the Haddam Neck Plant and Millstone Unit No. 1, respectively.
These matters have been the subject of frequent written and verbal communications between our respective Staffs in fulfill-ment of the license conditions for each facility.
Connecticut Yankee Atomic Power Company's (CYAPCO) and Northeast Muclear Energy Company's (NNECO) ongoing review and implementation of these require-ments has identified the need for clarification of the method of compliance for one SER ltem for each unit.
The details of the clarifications are provided in Attachment 1 for the Haddam Neck Plant, and Attachment 2 for Millstone Unit No. 1.
It is emphasized that while the method of compliance previously ageced upon is being revised, the proposed alternative is equivalent or superior to the original concept. The intent of the Staff requirements continues to be fulfilled.
1855 212 s oo2 0io 3YV Should you require any additional information to concur in our determination that the attached material is responsive to the license conditions, please advise accordingly.
Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY NORTilEAST NUCLEAR ENERGY COMPANY W. G. Counsil Vice President A ttachments 1855 215
DOCKET No. 50-213 ATTACIDIENT 1 HADDAM NECK PLANT FIRE PROTECTION MODIFICATIONS 1855 214 JAhTARY, 1980
NRC-SER ITE!! 3.1.16 - FLAME RETARDANT COATINGS NRC Concern (a)
A flame retardant coating will be applied to cables in the cable vault.
(b)
A flame retardant coating will be applied to safety-related cables routed in trays in the containment except for the upper head cables within the crane wall.
CYApCO Response The recommendation to provide flame retardant coating to cables as described above was generated during NRC's site fire protection inspection of CYApCO.
The concern was that all the cabling involved was not qualified to IEEE-383 and the required separation was not in strict conformance to Regulatory Guide 1.75.
CYApCO has evaluated its present arrangement with respect to contain-ment electrical penetrations and has decided to replace all existing assemblies.
This modification is scheduled to be performed during the 1980 refueling outage.
The new design for the electrical penetrations will incorporate many features which inherently benefit fire protection for both fire zone R-1 (containment cable vault) and fire zone R-4 (inside containment lower annulus area).
These special design features include:
(a)
All safety related cabling will be in conduit as it enters or leaves the penetration area, and is qualified to IEEE 383-1974.
(b)
All safety related cable will be routed in accordance with Regulatory Guide 1.75.
(c)
Safety related penetrations will physically be located at the lowest level of penetration stacking to reduce exposure to fire.
Based on the specific fire protection design features incorporated into the penetration replacement project, CYAPCO concludes that NRC's fire protection concerns for the referenced fire areas have been fully accounted for.
CYApCO requests that the requirement to apply flame retardant coatings to cables in the referenced areas be deleted in lieu of the modifica-tions noted above.
Should NRC need more information on the specifics of this modification, please contact Mr. Richard M. Kacich of our Licensing and Saf eguards Section.
1853 215
DOCKET NO. 50-245 ATTACIE4ENT 2 MILLSTONE NUCLEAR POWER STATION, UNIT NO. 1 FIRE PROTECTION MODIFICATIONS 1855 216 JANUARY, 1980
- I NRC - SER ITEM 3.1.14 NRC CONCERN A blast wall will be erected between the boiler room and the diesel generator Toom.
NNECO/MP-1 RESPONSE The recommendation to crect a blast wall between the diesel generator room and the boiler room was generated and discussed during NRC's site fire protection inspection for Millstone Unit No. 1.
The concern was that a boiler explosion in the auxiliary boiler room (fire zone T-9) could damage the emergency diesel generator in fire zone T-7.
Alsc of concern were the main supply feeds from the emergency gas turbine which are routed through the machine shop (also fire zone T-9).
NRC's recommendation was to supplement or strengthen the existing wall between fire zone T-7 and T-9 to withstand a potential boiler explosion.
The existing wall is a 12-inch thick reinforced block wall.
A review of the concern involved (damage to emergency diesel), the proposed modification (a blast wall) and discussions with the boiler manufacturer, has re alted in the conclusion that no additional wall or modification to exi ting wall was necessary.
Information received f rom the boiler manufacturer (attachment I) documents boiler explosion experience and their resulting affect. The experience is that boiler explosions result in boiler movement either forward or backwards.
The manufacturer states that they "have no knowledge of a pressure vessel moving sidewise from any type of fire side or water side failure condition."
1855 217
2 The type of failure expected from any similar steel cylindrical shaped construction would be an end type failure and this is consistent with actual manufacturer's experience.
The boilers at Mp-l are orientated or arranged so that an end failure would not have any adverse affect on the existing diesel room south wall (see Sketch Mp-1A).
Based on the manufacturer's experience, type of failure expected from a cylindrical type vessel (end failure), orientation of the boilers, and the nature of the potential explosion, NNECO concludes that the existing wall provides sufficient protection to the emergency diesel generator.
1855 2iB
I I
DLAKE EQUIPMENT COMPANY,1NC.
g' so oamwooo o=vs. stoowco. coan ecicut. osoor. mass ses usi September 26, 1979 Northeast Utilities Service Company P.O. Box 270 Hartford, Connecticut 06101 RE: Cleaver-Brooks Firetube boilers Hillstone Point Per your request, we have checked with Cleaver-Brooks regarding explosion occurrences of Firetube boilers similiar to the units you have in your Hillstone Point Facility, specifically in regard to the direction of movement should an explosion occur. The following is a quote from Mr. Syd Snow, Service Hansger for Firetube boilers with Cleaver-Brooks:
"Your question actually ask for our experience wherein an explosion would occur in a firetube unit and basically what direction of movement would the pressure vessel take if in fact, it moved off of its' initial foundation location.
Unfortunately, we have experienced such waterside explosions which stem from low water conditions, wherein the low water controls f ailed to shutoff the burner and the boiler eventually is fired dry with the resultant over heating of metal to a ducitle point, in most cases this is a cherry red condition, and the metal at that point rips open with the resultant violent release of expanding steam and virtually makes the pressure vessel into a rocket. The boiler, wherein the rupture of the pressure vessel occurs at the rear tube sheet would obviously move forward.
If such a rupture would occur at the front tube sheet, the pressure vessel would then obviously move rearward.
In this writer's experience, of some 30 years, we have no knowledge of a pressure vessel moving sidewise from any type of fireside or waterside failure condition. We have in fact had firetube boilers set side by side in a corrrnon boiler room, wherein one (1) unit has incurred a rupture at the rear tube sheet, chat unit was propelled forward and its' companion unit remained in operation, during the course of that explosion.
1855 2M
Page Two We do not feel that there is any danger to equipment that may be located to either side of a firetube boiler, other than the danger of falling debris or other structual parts wherein a building roof line may be damaged."
I hope the above information is adeauste and meets your needs.
If you have any questions, feel free to contact Mr. Snow directly, or the writer at this office.
Sincerely yours, BLAKE ECUIPMENT COMPANY, INC.
9 TD:sc cc: RE 55 220-
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