ML20212K403
| ML20212K403 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 01/27/1987 |
| From: | Miraglia F Office of Nuclear Reactor Regulation |
| To: | Mroczka E CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| NUDOCS 8701290067 | |
| Download: ML20212K403 (5) | |
Text
-
January 27, 1987 Docket No. 50-213-DISTRIBUTION:
DOCKET FILE NThompson m
NRC PDR FAkstulewicz Local PDR PAnderson ISAPD ACRS(10)
Mr. Edward J. Mroczka, Senior Vice President FMiraglia WJensen Nuclear Engineering ano Operations OELD CBerlinger Connecticut Yankee Atomic Power Company EJordan CThomas Post Office Box 270 BGrimes CLiang Hartford, Connecticut 06141-0270 JPartlow JNovak
Dear Mr. Mroczka:
HThompson 5UBJECT: AUGMENTED INSERVICE INSPECTION AND RESOLUTION OF ENVIRONMENTAL QUALIFICATION AND HIGH ENERGY LINE BREAK ISSUES By letters dated December 13, 1985 and August 11, 1986 and during a meeting with the staff on Septeimber 17, 1986, Connecticut Yankee Atomic Power Company (CYAPCo) responded to staff concerns regarding the reliance on the feed and bleed core cooling method to address issues associated with environmental qualification of certain equipment and for mitigating high energy line break (HELB) accidents outside containnent. Based upon these interactions, CYAPCo, in a letter dated December 5, 1986 proposed an augmented inservice inspection program for piping in the auxiliary steam supply lines and stated a willingness to submit a license amendment request formalizing the proposed augmented inspection program, if the staff believed that action was appropriate.
In a conference call on January 5, 1987, CYAPCo confirmed that the proposed augmented inspection program includes: 1) a volumetric and surface examina-tion of all new potential break locations during the next outage; 2) a volume-tric examination of each weld during each 31/3 year period; 3) a surface examination of each weld during each 3-1/3 year period; 4) and a monthly visual examination of each weld for possible leakage. The program for subsequent 10 year intervals includes requirements that a volumetric examination of each weld be performed once during the 10 year interval and visual examinations be per-formed semiannually.
If indications greater than allowed by Section XI of the ASME Code are discovered, the inspection program will revert to the inspection requirements identified for the first 10 year interval.
The staff has reviewed the augmented inspection program proposed in the December 5, 1986 letter and concludes that the proposed augmented inspection program for the auxiliary steam supply lines would meet all applicable regula-tory criteria and would resolve all staff concerns associated with environmental qualification and HELB issues for the Haddam Neck Plant.
Because the licensing basis for mitigating HELBs at Haddam Neck has evolved over a period of years, we have enclosed a summary description of our understanding of the evolution of i
the HELB licensing basis at the Haddam Neck Plant.
8701290067 870127 PDR ADOCK 05000213 0
PDR t
9 y-g n
.,4ga y
-,.,..._n y,.,,
-w_ _ _, _ _ _.,,.,.,,
, ~.
-n-,
-__,mmm
,,ww
Mr. Edward J. Proczka i The staff also concludes that a license amendment request to formalize this augmented inspection program should be submitted no later than 30 days from i
receipt of this letter. The formalization of the new program for the auxiliary J
steam supply system would be consistent with the licensing requirements of the limited augmented inspection program previously approved in 1977.
If you have any questions concerning this matter, please contact F. Akstulewicz, the Haddam Neck Project Manager.
1 Sincerely,
/s/
Frank J. Miraglia, Director Division of PWR Licensing-B Office of Nuclear Reactor Regulation
Enclosure:
As stated cc: See next page l
t
- See previous concurrence page N
kS der i
la ME*
5*
Ig/87 1/ag87 TCcJac CThonns i/ Ale ll +l%7 ISPAD*
ISAPD*
ISAPD*
PBEB*
PBEB>
AD:DPLB 6 FAkstulewicz:dj PAnderson CGrimes CCheng LMarsh DCrutchfield 12/20/86 12/20/86 12/22/86 1/(b/87 1/6/87 1/tt/87
Mr. Edward J. Mroczke Connecticut Yankee Atomic Power Company Haddam Neck Plant cc:
Gerald Garfield, Esquire Kevin McCarthy, Director Day, Berry & Howard Radiation Control Unit Counselors at Law Department of Environmental City Place Protection Hartford, Connecticut 06103-3499 State Office Building Hartfcrd, Connecticut 06106 Superintendent Haddam Neck Plant Richard M. Kacich, Supervisor RDF #1 Operating Nuclear Plant Licensing Post Office Box 127E Northeast Utilities Service Company East Hampton, Connecticut 06424 Post Office Box 270 Hartford, Connecticut 06141-0270 Wayne D. Romberg Vice President, Nuclear Operations Northeast Utilities Service Company Post Office Box 270 Hartford, Connecticut 06141-0270 Board of Selectmen Town Hall Haddam, Connecticut 06103 State of Connecticut Office of Policy and Management ATTN: Under Secretary Energy Division 80 Washington Street Hartford, Connecticut 06106 Resident Inspector Haddam Neck Nuclear Power Station c/o U.S. NRC P. O. Box 116 East Haddam Post Office East Haddam, Connecticut 06423 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406
., ~ - -
Enclosure
SUMMARY
OF LICENSING BASIS FOR MITIGATING A HIGH ENERGY LINE BREAK (HELB)
AT THE HADDAM NECK PLANT In response to a Conunission letter dated December 18, 1972, Connecticut Yankee Atomic Power Company (CYAPCo) performed a detailed evaluation of the potential consequences of a postulated rupture of high energy fluid piping systems outside the primary containment. The licensee identified three indepen-dent means of providing safe shutdown for every postulated break assuming the unavailability of offsite power and proposed additional modifications to provide additional protection. The staff concluded that, upon completion of the planned modifications, which included the addition of a motor driven auxiliary feedwater pump, at least two independent methods of completing plant cool down would be available and Haddam Neck could withstand the consequences of any HELB.
In February 1975, CYAPCo revised its HELB analyses in entirety. The evaluation criteria included the assumptions of loss of offsite power and a single failure.
The licensee again identified three independent methods of plant shutdown which in-cluded main feedwater system, emergency feedwater system and direct feeding through the emergency core cooling system (Method 3). The licensee also proposed an augmented inspection program and other plant modifications, such as restraints, barriers and encapsulation sleeves but withdrew the previous commitment to in-stall a motor-driven auxiliary feedwater pump.
In 1977, NRC issued Amendment No. 16 which approved the licensee's augmented inservice inspection (ISI) program and the proposed restraints, barriers and encapsulation sleeves. The staff's safety evaluation concluded that the aug-mented inservice inspection program assured the continued integrity of the high energy fluid piping. This conclusion meant that breaks in the piping covered by the augmented inspection program need rot be postulated as part of the HELB design basis. While not specifically stated in the safety evaluation, the pipe locations specified in the augmented inspection program were thought to represent a complete list of HELB locations requiring core cooling Method 3.
Because the augmented inspection program precluded the need to postulate breaks at these locations, it is not apparent that a detailed formal review of the licensee's core cooling Method 3 was performed at that time.
Prior to 1981, CYAPCo installed a non-safety related motor driven auxiliary feedwater pump. This pump was originally installed to provide a source of water for filling and hydrostatically testing the steam generators when the main and auxiliary feedwater sources were unavailable. While this pump was not included in the plant design for mitigating HELBs, it may provide an additional alternative (backup) should the normal main and auxiliary feedwater systems become unavailable.
The subiect of HELB concerns was raised again during the environmental qualifi-cation (EQ) reviews of the early 1980's. The licensee argued that it did not need to qualify components in the auxiliary feedwater system to a harsh environ-l ment because of prior approval of the feed-and-bleed core cooling method i
i L
o
_2_
(Method 3). The staff's contractor performing the EQ reviews was unable to resolve this issue with CYAPCo and requested that the staff resolve this problem with the licensee directly.
In September 1985, CYAPCo was formally notified that the staff could not accept the feed-and-bleed core cooling method as the primary safe shutdown method for mitigating design basis HELBs.
At CYAPCo's request, the staff and the licensee reviewed jointly the licensing record on HELB's again in an effort to substantiate the licensee's claim that the feed-and-bleed core cooling method had been previously reviewed and approved by the staff. CYAPCo provided specific references to SEP topic reviews and other licensing information.
Upon completion of this review, CYAPCo and the staff concluded that the licensing record on the resolution of the HELB issue was inconclusive; it was not clear why, given the original evaluation criteria, steam supply lines for the auxiliary feedwater system were not included in the original augmented ISI program, and that there was no evidence to suggest that the feed-and-bleed core cooling method was explicitly reviewed and approved for use in mitigating design basis accidents. This information was discussed with CYAPCo during the meeting on September 17, 1986.
On December 5, 1986, CYAPCo proposed to implement an augmented ISI program for 59 pipe weld locations on the steam supply lines in the auxiliary feedwater system. Consistent with the previously approved augmented ISI program (20 break locations involving 46 welds), the implementation of the licensee's updated program would provide reasonable assurance of continued integrity of high energy piping at the additional 59 weld locations i.e., that breaks need not be postulated at the monitored locations as part of the Haddam Neck HELB licensing basis.
In summary, the licensing basis for HELBs and Environmental Qualification of Electrical Equipment at the Haddam Neck Plant includes the augmented inservice inspection program for specific pipe locations, and the use of main or auxiliary feedwater systems. The use of feed-and-bleed core cooling is not included in the licensing bases at Haddam Neck. The staff does recognize, however, that feed-and-bleed core cooling could be available as an alternative (backup) means of mitigating HELBs in the unlikely event that an accident beyond the licensing basis should occur. Because of the uncertainties associated with the effecti-veness of feed-and-bleed core cooling, the staff has not performed a detailed l
review of the Haddam Neck response for this method nor attempted to quantify L
the margin of safety it provides.
.-