NRC Generic Letter 83-24, TMI Task Action Plan Item I.G.1, "Special Low Power Testing and Training," Recommendations for BWRS

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WASHINGTON, D.C. 20555

June 29, 1983

ALL BWR APPLICANTS FOR AN OPERATING LICENSE AND HOLDERS OF OPERATING LICENSES FOR GRAND GULF, LASALLE AND SUSQUEHANNA

Gentlemen:

Subject: TMI Task Action Plan Item I.G.1, "Special Low Power Testing and Training," Recommendations for BWRs (Generic Letter 83-24)

The present licensing process is a two-step process for which Task Action Plan Item I.G.1, as quoted from NUREG-0694, requires applicants for low power operating licenses to:

"Define and commit to a special low power testing program approved by NRC to be conducted at power levels no greater than 5 percent for the purposes of providing meaningful technical information beyond that obtained in the normal startup test program and to provide supplemental training."

Prior to issuance of a full power license, low-power licensees are to:

"Supplement operator training by completing the special low-

power test program. Tests may be observed by other shifts or repeated on other shifts to provide training to the operators."

PWRs, beginning with the licensing of Sequoyah 1 in 1980, have complied with the I.G.1 requirements by conducting special testing and training in natural circulation and simulated degraded AC power conditions. The staff has not required "follow-on" units to conduct these exercises if they were performed on the first unit and all licensed operators participated (e.g., Sequoyah 1 and McGuire 1 conducted a I.G.1 program, but Sequoyah 2 and McGuire 2 did not).

A meaningful I.G.1 program for BWRs comparable to the PWR program has not ben defined. The BWR Owners' Group initial response to TMI Item I.G.1 was that it should not apply to BWRs as there are no additional tests analogous to the PWR tests which would provide meaningful technical information and supplemental operator training. In a letter from D. B. Waters to D. G. Eisenhut dated February 4, 1981, the BWR Owners' Group subsequently proposed that BWR applicants meet the I.G.1 requirement by augmenting reactor operator participation in the initial test program and by some additional preoperational tests. After review of this response, it was the staff's position that, to ensure compliance with I.G.1, the BWR applicants be required to do some additional startup testing beyond that called for by Regulatory

.Guide 1.68 (and in addition to some "new" tests proposed by the BWR Owners' Group). The staff subsequently requested BWR applicants to commit to the recommendations of the Owners' Group and, in addition, to perform a "Simulated Loss of All A-C Power" (Station Blackout-SBO) test. The objective of the SBO test was to determine the temperature, pressure, and level responses and associated time constants of the reactor, drywell, containment, and vital spaces in event of a loss of heating, ventilation and air conditioning (HVAC) and cooling water, with decay heat being rejected to the suppression pool via the safety-relief valves. Decay heat was to be simulated by nuclear heat produced at lower power, or the test could be postponed until later in the fuel cycle when sufficient decay heat was available.

The staff has received commitments from each new operating license holder to conduct the test during the first fuel cycle when decay heat is available. However, the Susquehanna licensee, Pennsylvania Power & Light (PP&L), has indicated that a simulated loss of all AC power test would subject the drywell to a severe temperature and humidity transient having the potential of damaging equipment in the drywell. At least two other BWR licensees have indicated that they would terminate the test prior to exceeding certain temperature limits in the drywell. Upon further review of the basis for the requirement, the practicalities and value of such a test, and the proposed augmented Owners Group program, we conclude that the SBO test does not provide significant new information to justify its performance. Furthermore, since one of the original criteria for I.G.1 special tests (as stated in the Sequoyah SER) is that the test must not pose a hazard to plant equipment, the staff now recommends that the SBO test be deleted from the BWR I.G.1 staff position.

The staff finds that if it can be demonstrated that temperature and/or other SBO test conditions would adversely impact and pose a hazard to plant equipment, the BWR Owner's Group recommendations by themselves would constitute compliance with Item I.G.1, since performance of the SBO test under less adverse conditions would not provide significant benefit for either training or design feedback. Nor has the staff identified other special tests that should be performed at BWR's at this time. Therefore, the staff concludes that, unless the need is identified in the resolution of Generic Issue A-44, "Station Blackout", the SBO test should not be required at BWR's.

All applicants for an operating license are required to respond to this letter demonstrating the adverse impact the SBO test will have on their plant equipment, (i.e., a statement of conclusions and supportive evidence that loss of drywell cooling would pose a risk of damage to plant equipment in the drywell area) and confirming that the BWR Owner's Group recommendations will constitute compliance with Item I.G.1, or NRC consideration and documentation in the SER/SSER's. The remaining two holders of operating licenses (i.e., for Grand Gulf and LaSalle) must provide a similar response to this letter for NRC consideration in deleting the SBO test license condition cited in their operating license.

Darrell G. Eisenhut, Director Division of Licensing Office of Nuclear Reactor Regulation